Certified Neuroscience Registered Nurse (CNRN) Practice Exam

What type of inheritance pattern does neurofibromatosis follow in most cases?

1. X-linked dominant

2. Autosomal recessive

3. Autosomal dominant

4. Polygenic inheritance

The correct answer is: Autosomal dominant

Neurofibromatosis primarily follows an autosomal dominant inheritance pattern. This means that only one copy of the mutated gene is sufficient to cause the disorder. In the case of neurofibromatosis, if a parent carries the mutation responsible for the condition, there is a 50% chance that each child will inherit the disorder. This pattern of inheritance explains the occurrence of neurofibromatosis across generations in families, as affected individuals can pass on the gene to their offspring, regardless of the sex of the parent or child. Autosomal dominant conditions are also characterized by the presence of the disease in successive generations, and affected individuals typically have one affected parent. The severity of the condition can vary widely among individuals, even within the same family, which is a notable feature of neurofibromatosis. Understanding this inheritance pattern is crucial for genetic counseling and management of the condition.