Genetics

Genetic Inheritance Patterns Explained

Understanding how genetic conditions are inherited helps make sense of family history discussions and genetic counselling conversations.

Autosomal dominant
One copy of altered gene causes condition
Autosomal recessive
Both copies needed
X-linked
Gene on X chromosome — often affects males more

Inheritance Patterns Explained

PatternHow It WorksExample Conditions
Autosomal dominantOne altered gene copy from either parent causes the condition; affected parent has 50% chance of passing it to each childHuntington's disease, some familial hypercholesterolaemia
Autosomal recessiveBoth gene copies must be altered; carriers (one altered copy) are usually unaffected; two carrier parents have 25% chance of an affected childCystic fibrosis, sickle cell disease
X-linked recessiveGene located on X chromosome; typically affects males more severely as they have only one X chromosomeHaemophilia, Duchenne muscular dystrophy

Why This Matters for Families

Understanding the inheritance pattern of a condition in your family helps predict risk for other family members and future children, and guides decisions about genetic testing and counselling.
Genetic Counselling Provides Personalised GuidanceIf a genetic condition runs in your family, a genetic counsellor can provide detailed, personalised risk assessment and testing guidance specific to your family's situation — this basic overview is a starting point, not a substitute for professional counselling.
If both my parents are unaffected carriers, can I still have a genetic condition?
Yes — for autosomal recessive conditions, two unaffected carrier parents (each with one altered gene copy) can have an affected child if both pass on their altered copy, with a 25% chance for each pregnancy.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.