Genetics - Noonan Syndrome

Question 1

Definition

Answer 1

Genetic condition = number of different genes that cause Noonan syndrome
- Majority of cases are inherited in an autosomal dominant
- There is variation in the signs and symptoms of Noonan syndrome, depending on the underlying cause

Question 2

Signs and symptoms

Answer 2

• Short stature
• Broad forehead
• Downward sloping eyes with ptosis
• Hypertelorism (wide space between the eyes)
• Prominent nasolabial folds
• Low set ears
• Webbed neck
• Widely spaced nipples

Question 3

Associated conditions

Answer 3

• CHD = particularly pulmonary valve stenosis, hypertrophic cardiomyopathy and ASD
• Cryptorchidism (undescended testes) -> infertility. (Fertility is normal in women)
• Learning disability
• Bleeding disorders
• Lymphoedema
• Increased risk of leukaemia and neuroblastoma