Counsel a family on a new Prader-Willi diagnosis and the trajectory ahead — OSCE

Task

Counsel the parents. You have five minutes. Demonstrate an organised, empathic, and accurate explanation that addresses the five questions a fellowship communication station rewards: what the diagnosis means and why the earlier test missed it, what the trajectory looks like (neonatal feeding failure to hyperphagia), what the plan is for their son (growth hormone, dietary control, behavioural support), what the molecular subtype means for recurrence risk, and the honest truth about cure. The management framework follows the GeneReviews clinical guideline and the PWS growth hormone consensus. [1]

What the family needs to hear

Open by acknowledging the grief and naming the guilt. They feel the mother must have done something wrong during pregnancy — name this directly and dissolve it: Prader-Willi syndrome is caused by a genetic change that occurred as a chance event, a tiny missing piece on the chromosome that the father passed down, and no one caused it or chose it. Explain in plain language what the diagnosis means: their son's muscles are weak because a small group of genes that help regulate muscle tone, feeding, and growth is missing or switched off, and the brain does not receive the signals it needs to control appetite and growth normally. [1] [3]

Address the earlier test directly so they do not lose trust in the system. The standard karyotype was the right test to look at the overall chromosome structure, but it cannot see imprinting errors — the genes are present but switched off, like a light switch that is wired correctly but turned off. That is why we now ran the specific methylation test, which has found the answer. The methylation test works by checking which parent's genes are switched on, and in their son the father's copy is missing — this confirms Prader-Willi syndrome. [4]

The trajectory: what to expect

Lay out the trajectory honestly but with hope. Right now, the main problem is feeding — the muscles are too weak to suck effectively, and the nasogastric tube is the right support. This phase typically improves over the first year as muscle tone increases. Around 18 months to three years, a second phase begins: their son will develop a very strong interest in food, a genuine, physically-driven hunger that does not go away. This is the part that requires lifelong vigilance — locked food, structured meals, and a team approach to keep weight healthy. Be explicit that this is neurological, not a lack of willpower, and that with the right structure, their son can have a good life. [1]

The plan and the honest truth about cure

Describe the plan concretely: growth hormone therapy, which is standard of care and improves muscle tone, body composition, height, and development, and which we will start after a sleep study to make sure his breathing is safe overnight; dietary and environmental management that the family and school will build together; early intervention with physiotherapy, speech therapy, and occupational therapy; and regular check-ins with a multidisciplinary team that includes an endocrinologist, a dietitian, and a behavioural specialist. Be honest about cure: there is currently no medicine that reverses the missing genes, but there is a great deal we can do to support development, health, and quality of life, and research into new treatments is active and promising. [7] [1]

Recurrence risk and closing

Close with the recurrence-risk conversation, which is the counselling answer that the molecular subtype provides. The subtype is a paternal deletion, which is a sporadic chance event with a very low recurrence risk — less than one per cent for future pregnancies. This means that the chance of this happening again is very small, and we will offer testing in any future pregnancy if they wish. Give a written summary, a named contact, and a follow-up appointment. Thank them, affirm that early diagnosis is exactly the advantage their son now has — because we can start growth hormone and early intervention now, while his brain and body are still developing — and confirm that the plan is shared across the genetics service, the endocrinology team, the dietitian, and their general practitioner. [1] [4]