C. [A Minor] v Health Service Executive

APPROVED [2026] IEHC 234 THE HIGH COURT 2023 4334 P BETWEEN C. (A MINOR) SUING BY HER FATHER AND NEXT FRIEND PLAINTIFF AND HEALTH SERVICE EXECUTIVE DEFENDANT JUDGMENT of Mr. Justice Garrett Simons delivered on 22 April 2026 INTRODUCTION 1. The within proceedings comprise a personal injuries action alleging medical negligence. The Plaintiff is a minor child and was born in January 2020. The Defendant seeks to have the Plaintiff and her parents examined by a consultant clinical and biochemical geneticist. 2. To this end, the Defendant has issued a motion seeking the following relief: an order staying the proceedings until such time as the Plaintiff and her parents (a) attend for a clinical examination by the Defendant’s genetics expert, and (b) provide buccal swab samples to allow trio exome sequencing testing to be 2 conducted thereon. The proposed procedure is not invasive: it merely involves the taking of saliva swabs from the mouth. REPORTING RESTRICTIONS 3. The Plaintiff is a minor and is currently six years of age. The child has a medical presentation which, whatever its cause, affects her physical appearance and cognitive development. It would not be in the best interests of the child for her to be named in any media reportage of these proceedings. Although the child currently lacks the capacity to understand such matters, there is a risk that, depending on her future cognitive development, she may in time become aware of the reportage and appreciate its significance. It may cause undue stress to the child to be identified publicly as a person having this medical presentation. 4. Accordingly, the following reporting restrictions apply to these proceedings. An order is made pursuant to Section 45 of the Courts (Supplemental Provisions) Act 1961 prohibiting the publication of the names of the child and her parents and the address at which they reside. For the avoidance of doubt, any particulars referred to in this judgment may be reported. 5. The parties and any bona fide member of the media may apply, on seven days’ notice, to have these reporting restrictions varied or lifted. EVENTS ALLEGED TO CONSTITUTE MEDICAL NEGLIGENCE 6. It may assist the reader in a better understanding of the discussion which follows to provide a brief overview of the events which give rise to the claim for medical negligence. This overview simply recites the case as pleaded: it does not entail the making of any findings of fact by the court. 3 7. The Plaintiff was admitted to St. Luke’s General Hospital, Kilkenny on 9 February 2020. The Plaintiff’s presentation on admission included a two-day history of reduced feeding, with marked reduction in feeding on the day of presentation. It was reported that she repeatedly “threw her body back”, and that she had multiple episodes of vomiting, including projectile vomiting. It is pleaded that blood testing showed an abnormally low haemoglobin level. 8. The Plaintiff remained an inpatient in St. Luke’s General Hospital between 9 February and 12 February 2020. It is pleaded that her vomiting and regurgitation continued during this period and that she was noted to be pale. It is further pleaded that bilateral nystagmus was observed, including horizontal nystagmus on right gaze. The Plaintiff was discharged on 12 February 2020. No head/brain imaging was performed prior to discharge. 9. The discharge advice had been that the Plaintiff had cow’s milk protein allergy with associated gastro-oesophageal reflux. Dietary advice was given to the parents and an ophthalmology assessment was planned. 10. On 18 February 2020, the Plaintiff was again brought to St. Luke’s General Hospital because of parental concern about a worsened and worsening condition. It is pleaded that she had persistent vomiting, at times projectile, was sleepy and difficult to rouse, and that her mother observed the Plaintiff’s eyes to be more deviated to the right than previously. It is further pleaded that, notwithstanding the deterioration described, the Plaintiff’s parents were advised that her file was not available and they were advised to take her away. 11. On 21 February 2020, the Plaintiff was brought back to St. Luke’s General Hospital because of ongoing parental concern. It is pleaded that she had persistent and worsening vomiting, including projectile vomiting, and that her 4 parents were concerned about the amount of time she was sleeping, the difficulty in rousing her, and the extent of her distress and crying when awake. Her eyes were described as being “downwards” at times. It is further pleaded that the Plaintiff’s parents were reassured and advised to allow time for dietary changes to take effect. The Plaintiff was sent away again on 21 February 2020. 12. On 25 February 2020, a public health nurse reviewed the Plaintiff. It is pleaded that, for the first time since late January, the Plaintiff’s occipital-frontal head circumference was measured and recorded, and that findings included increased head circumference crossing centile spaces, increased/bulging fontanelle, and “sun-setting” eyes, with eye-rolling/nystagmus also noted. In response to those findings, the public health nurse arranged for the Plaintiff to re-attend urgently at St. Luke’s General Hospital. 13. A CT brain scan was performed at St. Luke’s General Hospital on 25 February 2020. It is pleaded that the scan demonstrated intracranial pathology consistent with hydrocephalus with associated haemorrhagic features. 14. Following the CT findings, the Plaintiff was transferred to the Children’s General Hospital, Temple Street, Dublin. An external ventricular drain was inserted in the early hours of 26 February 2020. It is pleaded that neurodevelopmental assessment occurred on 27 February 2020 and that an MRI brain scan on 28 February 2020 recorded findings consistent with grade IV intraventricular haemorrhage with parenchymal haemorrhage and surrounding oedema. 15. It is alleged that the Defendant was negligent in its assessment, investigation, diagnosis and management of the Plaintiff during the period between 9 February and 25 February 2020, and that those failures resulted in a delay in diagnosing 5 and treating intracranial pathology (hydrocephalus associated with intracranial haemorrhage/haematoma), with consequent progression of raised intracranial pressure and brain injury. 16. The pleaded case is that, by reason of these cumulative omissions and delays, appropriate neurosurgical drainage was not established until after severe hydrocephalus had developed, and that the delay materially contributed to permanent neurological injury and disability. 17. The amended defence makes the following admissions: “It is admitted that the Defendant breached its duty of care to the Plaintiff in the following respects: (i) The Plaintiffs occipito-frontal head circumference (OFC) should have been measured at each visit to the Hospital. (ii) It is admitted that on 18 February 2020, the post- haemorrhagic hydrocephalus could possibly have been diagnosed if an OFC measurement had been taken. (iii) It is admitted that on 21 February 2020, the post- haemorrhagic hydrocephalus would probably have been identified if an OFC measurement had been performed. (iv) No admissions are made concerning the impact of any failure to measure OFC on 18 or 21 February 2020 where it is unlikely any neuroimaging would then have been performed, in the case of 18 February 2020 at all, or in the case of 21 February 2020 urgently.” 18. It is not admitted that the alleged or admitted negligence and/or breach of duty and/or breach of statutory duty of the Defendant caused and/or contributed in a material way to the alleged injuries of the Plaintiff. 6 LEGAL TEST GOVERNING APPLICATION FOR STAY 19. The judgment of the Supreme Court in McGrory v. Electricity Supply Board [2003] 3 IR 407 confirms that the courts enjoy an inherent jurisdiction to stay proceedings, where justice so requires, in circumstances where a plaintiff in a personal injuries action refuses to submit to a medical examination. 20. The rationale underlying this inherent jurisdiction is explained as follows (at page 414 of the reported judgment): “Those principles, which have been adopted by courts in other common law jurisdictions, should also, in my view, be adopted in our jurisdiction. The plaintiff who sues for damages for personal injuries by implication necessarily waives the right of privacy which he would otherwise enjoy in relation to his medical condition. The law must be in a position to ensure that he does not unfairly and unreasonably impede the defendant in the preparation of his defence by refusing to consent to a medical examination. Similarly, the court must be able to ensure that the defendant has access to any relevant medical records and to obtain from the treating doctors any information they may have relevant to the plaintiff’s medical condition, although the plaintiff cannot be required to disclose medical reports in respect of which he is entitled to claim legal professional privilege.” 21. There was some debate at the hearing before me as to what the legal test governing an application for a stay should be. Counsel on behalf of the Plaintiff advocated for a three-stage test as follows. 22. First, the court should consider whether, in the interests of justice, the proceedings would have to be stayed if the proposed medical examination and the genetic tests are not undertaken. This requires an assessment of whether the testing is likely to assist in resolving the issues in controversy between the parties. Second, the court should examine whether the Plaintiff has advanced a substantial reason for refusing to undergo the genetic testing. Third, if a substantial reason is advanced, the court should then undertake a balancing 7 exercise between the parties’ competing rights, weighing the Defendant’s entitlement to defend the proceedings against the Plaintiff’s personal rights. 23. This three-stage test has been posited by reference to case law from England and Wales. Counsel refers, in particular, to Clarke v. Poole [2024] EWHC 1509 (KB). It should be noted that the Court of Appeal has since granted leave to appeal in that case: Clarke v. Poole [2025] EWCA Civ 447. It is not apparent whether the substantive appeal has yet been heard and determined. 24. As explained in the High Court judgment in Clarke v. Poole, the purpose of the introduction of the third stage of the test is to reflect what was described as the overarching question of whether it is just and proportionate to order a stay unless the particular plaintiff undergo medical testing. The judgment further explains that it is necessary to balance the competing rights, namely (i) the defendant’s right to defend itself in the litigation; and (ii) the plaintiff’s right to personal liberty. 25. Whilst respectful of the learning shown in the English case law, I am not satisfied that it is necessary to look beyond our own domestic case law. As appears from McGrory v. Electricity Supply Board, the overarching principle is that a plaintiff must not unfairly and unreasonably impede the defendant in the preparation of his defence by refusing to attend for a medical examination. It follows, from the use of the phrase “not unfairly and unreasonably”, that the court must engage in a balancing exercise. The right to defend proceedings must be balanced against the potential interference with a plaintiff’s rights, in particular, their right to privacy, confidentiality, and bodily integrity. 26. The balancing test required, in cases where it is sought to stay proceedings pending a medical examination, is broadly analogous to that which is performed 8 in the context of an application for the discovery of documents which are confidential to an individual. This approach has been discussed by the Court of Appeal in Ryan v. Dengrove DAC [2022] IECA 155 (at paragraph 67). The following principles are capable of being applied, with necessary modifications, to an application for a stay. 27. The Court of Appeal reiterates that confidentiality must ultimately yield to the interests of justice. Access to the courts, and the right to a fair determination of civil rights and obligations, are fundamental values under the Constitution of Ireland, the ECHR and the Charter of Fundamental Rights of the European Union. The Court of Appeal goes on, then, to say that a balance has to be struck between (i) the likely materiality of any given document to the issues likely to arise in the proceedings, and (ii) the degree of confidentiality attaching to it. A confidential document (and particularly one that is highly confidential) should not be directed to be discovered unless the court is satisfied that there is a real basis on which it is likely to be relevant at the hearing. The more material the document appears to be—the greater the likelihood that the document will have “some meaningful bearing on the proceedings”—the more clearly the balance will be in favour of disclosure. 28. Applying these principles, by analogy, to a medical examination, it follows that the first consideration to be addressed is the relevance or the materiality of the requested medical examination: it must be one which is intended to elicit information which is relevant to the proposed defence. If this is the position, then the court must next consider the grounds of opposition advanced by a plaintiff and balance the competing rights of the parties. This is essentially a two-limb test. Once the threshold of relevance is met, then the balancing 9 exercise involves a proportionality assessment. It is inherent to the second limb. The Plaintiff’s suggestion that “proportionality” should be separated out into an additional, third limb would tend to confuse matters. 29. The balancing exercise requires the court to weigh (i) the likely relevance/materiality of the results of the proposed medical examination to the issues in controversy between the parties against (ii) the potential interference with a plaintiff’s rights, in particular, their right to privacy, confidentiality, and bodily integrity. The court must consider the extent to which the outcome of the medical examination is likely to advance the moving party’s case or impair the opposing party’s case. 30. Accordingly, where a party seeks an independent medical examination or a specific test which engages heightened medical confidentiality or sensitivity (for example genetic or neuro‑physiological testing), the court will require a correspondingly clear demonstration that the results will likely have some meaningful bearing on the outcome of the personal injuries action. EVIDENCE BEFORE THE COURT 31. The Plaintiff’s side has not adduced any medical evidence in response to the motion. The only medical evidence before the court consists of three reports from the medical expert retained by the Defendant, Dr. Samantha Doyle. The second and third of these reports, dated June and November 2025, are supplemental to the first, principal report of 8 February 2025, and expressly address concerns raised by the Plaintiff’s legal team in relation to genetic testing. 32. Dr. Doyle is a consultant clinical and biochemical geneticist, and the clinical lead for perinatal genomics at the National Maternity Hospital. She is an expert 10 in perinatal genomics, and her work involves the care of families with genetic disorders. She holds a Master of Science in Genomics from the University of Birmingham; is a member of the British Society of Genetic Medicine; is the co- chair of the Prenatal Genomics Group, The British Society of Genomic Medicine; and is an executive board member of the British Society of Genomic Medicine. She is also an advisor to the National Institute for Health and Care Excellence. 33. Dr. Doyle has explained that she had been instructed to consider whether genetic factors might underlie aspects of the Plaintiff’s presentation, and, if so, what further investigations would be appropriate. The key findings of her first report are set out as follows: “While [the child] has had some genetic investigations performed including a chromosomal microarray in 2021 (Crumlin laboratory) and Prader Willi methylation studies in 2022 (Crumlin laboratory) the investigation performed are not comprehensive. I note that the endocrine team tested for Sotos syndrome but I cannot see the formal reports. In addition, in a recent letter there were plans to investigate for Malan syndrome, but those investigations did not take place, form the notes available to me. It is important to note that given the developmental delay, early onset obesity, dysmorphic features and ventriculomegaly a genetic diagnosis is likely in [the child]. The recommendations in a case like this is for extensive investigations in the form of exome sequencing or genome sequencing and a review with Clinical genetics. I cannot see that this has happened to date. In additional, the low factor 8 levels and apparent family history of this has not been reviewed from a genetic perspective. The clinicians involved in [the child’s] care have had suspicions about an underlying genetic diagnosis and I concur with their concerns. In order to progress the investigations that are required a full assessment by a Clinical Geneticist is required. While [the child] appears dysmorphic in the pictures in the files I have seen, it is possible that there are additional features which would only be detected after a full clinical examination. 11 While some genetic investigations have taken place, these have been limited. A chromosomal is a first line genetic test performed to look at a child’s chromosomes. For context, we usually have 46 chromosomes in each cell of our bodies, which come in 23 pairs. One copy of each pair comes from our mum and one from our Dad. Pairs 1-22 are the same in males and females, whereas the 23rd pair (our sex chromosomes) differ according to our sex. Males have one X chromosome and one Y chromosome (46XY), whereas females have 2 X’s (46XX). Our genes, the instructions which make a person, are carried on chromosomes, with each gene having a specific location on a chromosome. The testing to date has focussed on chromosome analysis and analysis for Prader Willi syndrome and Sotos syndrome. There are 2 syndromes out of almost 8,000 known rare genetic syndromes. There has been very little analysis of the sequencing of [the child’s] genes. This is recommended in a clinical presentation like [the child’s]. There is increasing data emerging to say that trio exome sequencing in a case like this can make a monogenic diagnosis in as many as 50% of cases. Analysis of parental DNA as part of the process is important to allow us determine the likelihood that a genetic variant in [the child] is causing her problems and recommended as best practice. In this case, I have been asked to give an opinion regarding the contribution of a genetic diagnosis to [the child’s] phenotype. It is my opinion that there is likely a genetic diagnosis here which has not been discovered yet as [the child] has never been reviewed by clinical genetics and has only had basic testing. In order to be able to comment any further, I need to meet with [the child] and her parents in clinic. At that appointment I will examine [the child] and take a family history. I will need to perform more genetic investigations. The clinical assessment will be important in deciding which tests are appropriate. This will likely involve trio exome sequencing. This is the gold standard test in a case like this. This will involve sequencing the DNA from [the child] and her parents. The analysis will primarily focus on [the child] and the parental samples will be used for comparison. In rare scenarios, something relevant to other family members might be detected. These investigations will take 6-8 weeks. I would be grateful to receive the formal report for the testing for Sotos syndrome which is referred to in the notes but not in the files. 12 Summary I feel that [the child] has an underlying genetic diagnosis based on the information currently available to me. To be more comprehensive in my assessment for the court, I need to meet [the child] and her parents in clinic and perform more genetic investigations. The investigations are performed on a sample of DNA taken from a buccal swab (from inside the mouth) which is not painful to obtain. In order to extract DNA, [the child] and her parents should not eat, drink or smoke for 30 minutes before meeting me in clinic. Following these assessments I will be in a position to provide an updated report regarding the contribution of a genetic diagnosis to [the child’s] phenotype.” *Footnotes omitted 34. As to process, Dr. Doyle has described a series of safeguards which she proposes to implement to ensure that any investigation is proportionate, ethically sound, and tightly confined to the questions which arise. She will provide pre‑test genetic counselling to the family, explaining the nature of the test, the range of possible outcomes, the implications for relatives, and the handling of any incidental findings. Consent will be documented by way of “Record of Discussion” forms for the child and for each parent, and post‑test counselling is offered if a diagnosis is made. 35. Sampling will be by buccal swab only. It will include the Plaintiff and both parents in order to enable parental comparison at the interpretation stage. The tubes will be labelled with two unique identifiers and first processed at the National Maternity Hospital laboratory before courier dispatch to The Doctors Laboratory in London. Depending on the analysis required, specialist testing will be undertaken in accredited facilities, including Fulgent Genetics in the United States for trio exome sequencing and, where appropriate, an NHS specialist laboratory. The results will be returned to Dr. Doyle via an encrypted 13 secure portal. Dr. Doyle proposes that the laboratories retain DNA for a period of twelve months, solely to permit necessary reflex testing without re‑sampling, after which the DNA is securely discarded. Samples are not used in a biobank. The DNA is not shared with third parties, and the sequencing data is not shared either. 36. Analysis will be strictly phenotype‑driven. Dr. Doyle said that benign or likely benign variants are not reported under international variant‑interpretation frameworks; in children, adult‑onset conditions are not reported; healthy carrier status is not reported; and secondary‑findings gene lists, which are routinely reviewed in some other jurisdictions, are not reviewed in Europe absent a specific clinical reason. She underlined that these constraints are explained at the counselling stage and that the objective is to confine reporting to variants which plausibly explain the phenotype under investigation. 37. As to laboratory assurance, Dr. Doyle stated that she uses accredited clinical laboratories and identified the quality systems relevant to the facilities she proposes to employ. In particular, The Doctors Laboratory participates in external quality schemes (including GENQA, ISFG, EMON, UKNEQAS, ECAT and LabQuality), while Fulgent Genetics is accredited by CLIA, CAP, ISO and the California Department of Public Health. She has used these providers consistently since 2021 and is not aware of errors in their work, nor of concerns amongst international colleagues as to the quality of the testing undertaken. 38. Dr. Doyle also indicated that—should the family prefer—a referral can be made to another clinical geneticist to undertake the assessment and any testing. In any event, results will be shared with the parties and the family, and a report then 14 prepared for the court following clinical review and analysis. She reiterated the anticipated six‑to‑eight‑week timeframe from sampling to result for trio exome sequencing and emphasised that this process, including the counselling and consent steps, is designed to minimise intrusion while addressing, in a focused way, the question of whether a genetic diagnosis underlies aspects of the Plaintiff’s presentation. 39. Dr. Doyle has explained in her third report (letter dated 25 November 2025) that, in her expert opinion, a genetic diagnosis in this case would provide therapeutic benefit. She has explained that, for children with a known genetic condition, it is possible to provide a prognosis and discuss the natural history of that particular diagnosis which facilitates screening for known complications, enabling early management, often before symptoms appear. By way of example, she observed that in cases of early onset obesity there may be specific metabolic health abnormalities which could be detected early in some genetic conditions, allowing prevention or early detection of complications like high cholesterol, high blood sugar levels, etc. Dr. Doyle further stated that where a specific genetic diagnosis is made, there may be specific treatments which could improve quality of life, noting that there are increasing gene therapies available for rare genetic conditions and that to access those, a molecular diagnosis is required. Dr. Doyle has also explained that it is important to identify a genetic diagnosis, as there are specialist clinics for some of those conditions where children are cared for by a multi-disciplinary team with expertise in the specific genetic condition. She added that, for the families of a child with a rare disease, having access to support from other families with affected children can be an “invaluable lifeline” and that a genetic diagnosis is also helpful in deciding what 15 therapies a child requires and is often considered when allocating resources. 40. As explained earlier, the Plaintiff’s side has not filed any medical evidence in response. A solicitor acting on behalf of the Plaintiff has filed an affidavit which consists largely of legal submission. The affidavit purports to criticise certain aspects of Dr. Doyle’s evidence. This is entirely inappropriate: the solicitor has neither the requisite independence nor the expertise to offer any admissible opinion on genetic testing. 41. It is correct to say that the onus lies on the Defendant, as the moving party in the motion, to establish that the results of the medical examination and genetic testing are likely to assist in resolving the issues in controversy between the parties. The Defendant has discharged this onus, and the Plaintiff has put forward no expert evidence to the contrary. DISCUSSION RELEVANCE / MATERIALITY The “indivisible injury” argument 42. One of the principal arguments advanced on behalf of the Plaintiff is to the effect that the proposed genetic testing does not fulfil the criterion of relevance. This argument is predicated on the fact that the Defendant has admitted, in its formal defence to the proceedings, that had certain measurements been taken in February 2020, the Plaintiff’s post-haemorrhagic hydrocephalus could have been diagnosed and identified earlier. Crucially, the Defendant makes no admissions concerning the impact of the failure to carry out these measurements. 43. The Plaintiff’s legal team seeks to rely on these limited admissions to construct an argument that she is entitled to recover—as against the Defendant— 16 compensation for one hundred per cent of the physical impairments, cognitive impairments and behavioural problems suffered by her. It is contended that the Plaintiff has suffered an “indivisible injury”. More specifically, it is contended that if the court of trial were to make a finding, on the balance of probabilities, that the delay in diagnosis of, and provision of appropriate intervention for, the Plaintiff’s intracranial pathology had made a contribution to the Plaintiff’s injury that was greater than negligible, then the Plaintiff would be entitled to succeed in recovering damages as against the Defendant in respect of the entirety of her current medical presentation. 44. Counsel on behalf of the Plaintiff places particular reliance upon CNZ (by her father and litigation friend MNZ) v. Royal Bath Hospitals NHS Foundation Trust [2023] EWHC 19 (KB), 192 BMLR 94. There, the High Court of England and Wales found that a negligent delay of six and a half minutes in the delivery of a baby materially contributed to the baby’s profound hypoxic-ischaemic injury, and that the claimant was entitled to recover one hundred per cent of damages because the functional outcome “but for” the negligence could not be determined. 45. There is simply no medical evidence before the court at this time which would allow it to make even a preliminary assessment of whether the Plaintiff has any realistic prospect of relying on the “indivisible injury” principle. This principle does not give rise to a presumption of causation; still less does it reverse the burden of proof. Rather, the principle addresses the difficulty that can arise when a negligent act has been found, on the evidence, to have contributed to an injury, but the precise extent of that contribution cannot be determined. The submission invites the court to speculate, in the absence of any evidence, that the events of 17 February 2020 have made a contribution to the Plaintiff’s current medical presentation. 46. For completeness, it should be explained that the circumstances of CNZ (by her father and litigation friend MNZ) v. Royal Bath Hospitals NHS Foundation Trust are distinguishable from those of the present case in the following respects. 47. First, the causal mechanism was not in dispute in CNZ. It was accepted by both parties that hypoxia causes progressive brain injury over time, and that the negligent delay extended the period during which the baby was exposed to hypoxia. The only question was whether that additional period of hypoxia materially worsened the functional outcome. The court had clear expert evidence before it which established the biological pathway by which the negligent delay contributed to the injury. In the present case, no equivalent evidence has yet been adduced. There is no expert evidence whatsoever before this court identifying a biological mechanism by which the admitted negligence in February 2020 caused or contributed to the specific impairments from which the Plaintiff suffers. 48. Second, the negligent act and the injury in CNZ operated within a single, continuous, and well-understood pathological process: evolving hypoxic- ischaemic encephalopathy. The delay formed part of the temporal continuum of that process, and it was scientifically uncontroversial that reducing the period of hypoxia would, on the balance of probabilities, have reduced the severity of injury. It is not at all obvious that a similar single, continuous process occurred in the present case. 49. Third, the controversy in CNZ was one of quantification, not of contribution. The court accepted that the delay had contributed to the injury; the difficulty was 18 in specifying the precise degree to which the neurological outcome would have differed but for that contribution. The “indivisible injury” principle seeks to address that difficulty. In the present case, the Defendant disputes that the events of February 2020 have made any contribution to the Plaintiff’s current medical presentation. There is no expert evidence before the court, in the context of this motion, to suggest that the Plaintiff’s contention to the contrary is correct. 50. The other cases cited on behalf of the Plaintiff are distinguishable on similar grounds. In Bailey (by her father and litigation friend) v. Ministry of Defence [2008] EWCA Civ 883, [2009] 1 WLR 1052, 103 BMLR 134, the Court of Appeal of England and Wales held that in a case where medical science cannot establish the probability that “but for” an act of negligence, the injury would not have happened but can establish that the contribution of the negligent cause was more than negligible, the “but for” test is modified, and the claimant will succeed. In Williams v. Bermuda Hospitals Board [2016] UKPC 4, [2016] AC 888, 150 BMLR 1, the Privy Council confirmed that the material contribution test applies where a negligent cause forms part of a cumulative process leading to an indivisible injury. In each case, the finding of contribution was grounded in evidence. Neither judgment stands as authority for the proposition that a court may infer causal contribution in the absence of evidence establishing such contribution. 51. In summary, the only expert evidence before the court on this motion is that of Dr. Samantha Doyle (summarised above). This expert evidence indicates that given the developmental delay, early onset obesity, dysmorphic features and ventriculomegaly, a genetic diagnosis is likely in this case. On the basis of this currently uncontradicted evidence, I am satisfied that the proposed medical 19 examination is not only relevant, but that the results of same will likely have some meaningful bearing on the outcome of the proceedings. Prior genetic investigations 52. It is submitted on behalf of the Plaintiff that the prior genetic investigations which have been carried out were extensive and negative. It is further submitted that the Defendant has identified no concrete pathogenic hypothesis that would justify revisiting the issue. 53. I am satisfied that these submissions are inconsistent with the expert evidence before the court. Dr. Doyle has outlined the genetic work which has been carried out to date and explained why, in her expert opinion, it is incomplete for present purposes. She noted the chromosomal microarray in 2021 and the Prader–Willi methylation and copy‑number studies in 2022, both of which were non‑diagnostic; she further noted a macrocephaly panel performed by whole‑exome enrichment at CeGaT in early September 2022 which did not identify a causative variant but recommended trio exome sequencing and Beckwith–Wiedemann syndrome testing; and she recorded that Beckwith– Wiedemann analysis performed in October 2023 was negative. 54. Dr. Doyle’s expert opinion is that there has been little, if any, analysis which incorporates parental comparators, and that a phenotype‑driven trio exome, using parental samples to assist interpretation, represents the “gold standard” approach in a case such as this. BALANCING EXERCISE 55. The Plaintiff’s parents raise objections grounded in privacy and autonomy. It is further submitted that genetic information inherently engages the privacy 20 interests of biological relatives. 56. I am satisfied that Dr. Doyle’s proposed process adequately addresses these concerns: any investigation would proceed only following pre‑test counselling and informed consent, recorded on “Record of Discussion” forms for the child and each parent; sampling is by non‑invasive buccal swab; family members who prefer may be referred to a different consultant geneticist; and results are routed via the legal teams. Dr. Doyle has offered to provide post‑test counselling and clinical sign‑posting. 57. The Plaintiff’s parents are also concerned about incidental and secondary findings—such as adult‑onset risks or carrier states—citing the qualitative burden of being required to choose whether to receive such information. Again, I am satisfied that these concerns have been adequately addressed. Dr. Doyle has explained that, in accredited clinical laboratories, incidental findings are reported only in rare circumstances; that in Europe secondary findings are not reviewed or reported absent clinical indication; that adult‑onset findings in children and healthy‑carrier status are not reported; that in phenotype‑driven trio exome “off‑phenotype” genes are sequenced but not analysed; and that the possibility of incidental findings is addressed expressly during pre‑test counselling as part of consent. Data security 58. The Plaintiff’s parents object on grounds of data security, “function‑creep”, and laboratory quality, referring to concerns about “poor quality foreign laboratories”, and citing risks of mislabelling, contamination, interpretive error and onward reuse or re‑analysis beyond the original purpose. 59. I am satisfied that the safeguards identified by Dr. Doyle address this objection. 21 These safeguards have been summarised at paragraphs 35 to 37 above. Role of parents 60. Counsel for the Plaintiff submits that it would be improper to stay the child’s case unless a “third party”, i.e. the Plaintiff’s own parents, provide a specimen for the genetic testing. 61. It is artificial to attempt to characterise the parents as third parties. The parents are actively involved in the pursuit of the personal injuries action. The father is acting as the child’s “next friend” for the purpose of the litigation. In this capacity, the father is directing the litigation and instructing the legal team. Alleged delay in filing motion 62. Counsel on behalf of the Plaintiff submits that the court should refuse to hear the motion by reason of delay on the part of the Defendant. It is said that the Defendant failed to comply with a court direction of 11 April 2025 to bring a motion “expeditiously”. (There does not appear to be any court order to this effect). The motion was filed on 21 July 2025. In the event, the motion only came on for hearing on 6 February 2026. If and insofar as the pursuit of the stay application has resulted in any delay, same is largely a function of the pressure on the courts’ lists rather than of any supposed delay in the filing of the motion. 63. I have liaised directly with the Judge in Charge of the Clinical Negligence List (Coffey J.), who has since assured the parties that the action will be specially fixed for hearing at the earliest date that is convenient to them. It follows that no material prejudice has been caused to the Plaintiff by the alleged delay in filing the motion: the parties have not lost the benefit of a specially fixed hearing date. 22 CONCLUSION AND PROPOSED FORM OF ORDER 64. For the reasons explained, I have concluded, on the basis of the expert evidence filed, that the results of the medical examination and genetic testing are not only likely to assist in resolving the issues in controversy between the parties, but that the results are likely to have a meaningful bearing on the outcome of the personal injuries action. If the cause of the child’s medical presentation is established at trial to be genetic, and if no expert evidence is adduced to establish that the events of February 2020 made a contribution to her current medical presentation, then the Plaintiff’s case would likely have to be dismissed. It should be emphasised that it remains open to the Plaintiff to adduce such expert evidence at the trial of the action. 65. On the other side of the scales, I have carefully considered the grounds of opposition to the genetic testing; and have concluded that the balance of justice lies in favour of staying the proceedings pending the carrying out of same. The Defendant’s right to defend the proceedings would be impeded in the absence of genetic testing, and the concerns raised by the Plaintiff’s parents have been comprehensively addressed by the proposed process. 66. Accordingly, an order will be made staying the proceedings until such time as the Plaintiff and her parents (a) attend for a clinical examination by the Defendant’s genetics expert, and (b) provide buccal swab samples to allow trio exome sequencing testing to be conducted thereon. 67. As to the incidence of legal costs, the default position is that costs follow the event, i.e. the successful party will normally be entitled to recover its costs as against the unsuccessful party. Insofar as the costs of the trial of an action are concerned, this general principle is stated at Section 169 of the Legal Services 23 Regulation Act 2015. The position in relation to a pre-trial or interlocutory motion, such as that the subject-matter of this judgment, is governed by Order 99, rule 3 of the Rules of the Superior Courts which provides, in relevant part, that the High Court, in considering the awarding of the costs of any step in any proceedings, shall have regard to the matters set out in Section 169(1) of the above Act where applicable. Order 99, rule 3 further provides that the High Court is obliged, upon determining any interlocutory application, to make an award of costs save where it is not possible justly to adjudicate upon liability for costs on the basis of the interlocutory application. The type of circumstances in which it might not be possible to adjudicate on costs are discussed in ACC Bank plc v. Hanrahan [2014] IESC 40, [2014] 1 IR 1 (at paragraphs 8 to 11 of the reported judgment). Where, as in the present case, the issues arising on the pre- trial motion are self-contained and will not have to be revisited at the trial of the action, it is appropriate for the motion judge to determine the incidence of costs. 68. My provisional view is that the Defendant, having been entirely successful in its motion, is entitled to recover the costs of the motion as against the Plaintiff (to include reserved costs and the costs of the written legal submissions). It is proposed to put a stay on the execution of the costs order until the substance of the proceedings has been determined at the level of the High Court, i.e. following the trial of the action. If either party wishes to contend for a different form of costs order, they should apply to the registrar within fourteen days and arrange to have the matter relisted before me. Appearances Cian T. O’Mahony for the plaintiff instructed by Noonan Linehan Carroll Coffey LLP Michael Binchy SC (with Luan Ó Braonain SC) for the defendant instructed by Hayes Solicitors LLP