رجل عمره ٤٠ سنة بدأت عنده منذ سنة حركات لا إرادية متقلبة في اليدين والوجه، وتغيرات مزاجية وعصبية، ونسيان. والده كان عنده نفس المرض وتوفي في الخمسينات. عنده ثلاثة أبناء. ما احتمال انتقاله لأبنائه؟

A 40-year-old man has had a year of fluctuating involuntary movements of the hands and face, mood changes, irritability and forgetfulness. His father had the same disease and died in his fifties. He has three children. What is the chance of passing it to his children?

1. 50% for each child, as it is autosomal dominant
2. 100%, but for sons only
3. 25%, as it is autosomal recessive
4. Zero, because the disease is not inherited

Answer: A) 50% for each child, as it is autosomal dominant. Huntington’s disease is autosomal dominant, so each child has a 50% risk. It causes chorea, cognitive and psychiatric decline and raised suicide risk; genetic counselling is advised.