Inheritance patterns (autosomal recessive, autosomal dominant, X-linked)

Genetic conditions caused by a single gene can be inherited in different patterns, which affect the chance of a child being affected. In autosomal recessive inheritance (as with beta-thalassaemia or sickle-cell disease), a child is usually affected only if both parents are carriers and each passes on an altered copy of the gene, giving roughly a one-in-four chance with each pregnancy when both parents are carriers. In autosomal dominant inheritance (as with some BRCA1/BRCA2 or Lynch syndrome variants), only one altered copy is needed to increase risk, and a child of an affected or carrier parent has roughly an equal chance of inheriting it. In X-linked inheritance (as with haemophilia or Duchenne muscular dystrophy), the relevant gene sits on the X chromosome, so the pattern and chance of a child being affected differs for sons and daughters, and female carriers are often unaffected or mildly affected while their sons are at higher chance of being affected. These patterns are general principles; genetic counselling can apply them to a specific family's genetic result and history, since actual chances can vary with the specific variant and family circumstances.

Also known as: autosomal recessive, autosomal dominant, X-linked inheritance, genetic inheritance

Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.