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Exome/genome – consanguinity — RACP Paediatrics MCQ

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HardGeneticsExome/genome – consanguinityRACP Paediatrics

A consanguineous couple has a child with a severe undiagnosed syndrome (developmental delay, seizures, microcephaly). Standard investigations (karyotype, CMA, metabolic screen) are normal. What is the most appropriate next genetic investigation to maximise diagnostic yield?

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Correct answer: A — Chromosomal microarray recommended

In a child from a consanguineous family with an undiagnosed syndrome and negative standard investigations, whole exome or genome sequencing (preferably trio with both parents) has the highest diagnostic yield. Consanguinity increases the prior probability of autosomal recessive conditions, and homozygosity mapping from exome data can further increase diagnostic sensitivity.

Reference: RACP Paediatric Curriculum – Genetics; RCH Melbourne – 2023 – Undiagnosed Conditions CPG