Background
On 22nd April 2026, Mr Justice Garrett Simons delivered judgment in C (a Minor) v Health Service Executive [2026] IEHC 234, a complex medical negligence action arising from alleged failures in the diagnosis and management of intracranial pathology in an infant.
The plaintiff, a child born in January 2020, presented on multiple occasions to St Luke’s General Hospital, Kilkenny in February 2020 with concerning symptoms including persistent vomiting, poor feeding, lethargy, abnormal eye movements and neurological signs. No neuroimaging was performed until 25 February 2020, when a CT scan revealed hydrocephalus with intracranial haemorrhagic features. The child was transferred for neurosurgical treatment and subsequently suffered permanent neurological injury and disability.
The claim alleges that the Health Service Executive (‘HSE’) negligently failed to assess, investigate, diagnose and manage the child’s condition over a period of approximately two weeks, resulting in delayed intervention and avoidable brain injury.
In its defence, the HSE admitted breach of duty in failing to measure the child’s occipito‑frontal head circumference on certain attendances, but expressly did not admit causation, maintaining that it was not established that earlier diagnosis would have altered the outcome.
The central issue before the court was not liability, but whether the defendant was entitled, at an interlocutory stage, to stay proceedings pending genetic examination and trio exome sequencing of the child and her parents.
The application
The defendant applied to stay the proceedings unless the child and her parents agreed to:
- a clinical examination by a consultant clinical and biochemical geneticist; and
- the provision of buccal (saliva) swab samples to permit trio exome sequencing.
The defendant contended that the child’s presentation (including developmental delay, dysmorphic features, early onset obesity and ventriculomegaly) was suggestive of an underlying genetic condition which could provide an alternative explanation for some or all of the child’s impairments. If established, this would have a direct bearing on causation, contribution and the viability of the claim.
The plaintiff opposed the application on grounds including privacy, bodily integrity, data protection, delay, and relevance. It was argued that the child had suffered an “indivisible injury” and that, if negligence contributed to injury to any degree more than negligible, the defendant would be liable for 100% of the damages irrespective of any genetic contribution.
Decision
The High Court granted the defendant’s application and ordered that the proceedings be stayed pending genetic examination and trio exome sequencing.
In a detailed and careful judgment, Mr Justice Simons reaffirmed several fundamental principles of clinical negligence litigation.
Relevance and causation
The court confirmed that medical negligence claims do not give rise to any presumption of causation. Even where breach of duty is admitted, a plaintiff must still prove that the negligence caused or materially contributed to the injury complained of.
The court was particularly critical of the plaintiff’s reliance on the “indivisible injury” doctrine as a means of resisting investigation. Mr Justice Simons emphasised that this principle does not reverse the burden of proof and only applies after causative contribution has been established on the evidence. It cannot be used to avoid inquiry into alternative explanations for injury.
In the absence of any expert evidence from the plaintiff addressing causation, the court accepted the uncontradicted evidence of the defendant’s genetic expert that a genetic diagnosis was likely and that further investigation would have a meaningful bearing on the outcome of the claim.
Defendants’ right to defend
The court reiterated that a plaintiff who brings a personal injury claim necessarily waives aspects of medical privacy to the extent necessary to permit a fair defence. A plaintiff must not unfairly or unreasonably impede a defendant’s ability to prepare its case.
Where a proposed examination or test is relevant and proportionate, the court is entitled to intervene to ensure the defendant’s right to defend proceedings is not undermined.
Importantly, the court drew a clear distinction between speculative investigation and targeted testing. Here, the proposed genetic testing was said to be the gold‑standard investigation, tightly confined, non‑invasive and supported by agreed safeguards around consent, counselling, data security and confidentiality.
Balancing rights
Although acknowledging the sensitive nature of genetic information, the court was satisfied that the process proposed by the defendant’s expert adequately protected the child and her parents’ rights to privacy, bodily integrity and autonomy.
The court rejected arguments that requiring parental samples was improper, describing it as artificial to characterise parents as third parties where they were actively directing the litigation as next friend.
Comment
This is a highly significant decision for defendants, insurers and medical practitioners involved in clinical negligence litigation.
The judgment reinforces that causation remains a live and central issue, even where breach of duty is admitted. Courts will not permit plaintiffs to short‑circuit causation analysis through indivisible injury arguments unsupported by expert evidence.
Equally, the decision confirms that defendants are entitled to fully investigate alternative aetiologies, including genetic causes, where such investigation is likely to have a meaningful bearing on liability or quantum. The court will support proportionate and ethically sound testing where refusal would impede a fair defence.
For medical practitioners, the case also underscores the importance of careful documentation, early consideration of differential diagnoses and the complex interplay between alleged medical negligence and underlying congenital or genetic conditions.
Key takeaways
- Admission of breach does not equate to admission of causation.
- The “indivisible injury” doctrine does not remove the plaintiff’s burden to prove causative contribution.
- Defendants are entitled to pursue relevant and proportionate genetic investigations to explore alternative explanations for injury.
- Courts will actively balance privacy rights against the right to defend proceedings, particularly where safeguards are in place.
- Failure to engage with genetic or alternative causation evidence may prove fatal to a claim at trial.
This judgment provides robust guidance on the evidential and procedural discipline required in complex medical negligence claims and is likely to influence both case strategy and expert instruction at an early stage going forward.
