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CVS – early diagnosis — RACP Paediatrics MCQ

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ModerateGeneticsCVS – early diagnosisRACP Paediatrics

A couple has a child with cystic fibrosis (both parents are confirmed carriers of different CFTR mutations). They wish to have another child and want the earliest possible diagnostic test in pregnancy. At what stage can definitive prenatal genetic diagnosis be obtained?

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Correct answer: D — Chorionic villus sampling (CVS)

Chorionic villus sampling (CVS) can be performed from 11-14 weeks gestation and provides fetal tissue for genetic analysis. It is the earliest invasive diagnostic test available. Amniocentesis is performed from 15-16 weeks. Both carry a small procedural miscarriage risk (~0.1-0.3%). For couples wishing to avoid an affected pregnancy, preimplantation genetic testing with IVF is an option.

Reference: RACP Paediatric Curriculum – Genetics