What is the inheritance pattern of PRA?

What is the inheritance pattern of PRA?

• A. Autosomal dominant
• B. X-linked recessive
• C. Autosomal recessive
• D. Mitochondrial

Answer: (C)

PRA is most often inherited as autosomal recessive, meaning two copies of a mutated gene are needed for the condition to manifest. Carriers have one mutated gene but typically show no symptoms. In families, you may see unaffected parents who have affected children, and the risk for each child is 25% if both parents are carriers. This pattern helps explain why PRA can appear in siblings without either parent being affected and why consanguinity increases risk. In contrast, autosomal dominant would show the trait in every generation, X-linked recessive would more often affect males with carrier mothers, and mitochondrial inheritance would pass from mother to all her children. Because PRA commonly follows the two-mutant-allele pattern with carrier parents and affected offspring, autosomal recessive is the best fit.

PRA is most often inherited as autosomal recessive, meaning two copies of a mutated gene are needed for the condition to manifest. Carriers have one mutated gene but typically show no symptoms. In families, you may see unaffected parents who have affected children, and the risk for each child is 25% if both parents are carriers. This pattern helps explain why PRA can appear in siblings without either parent being affected and why consanguinity increases risk. In contrast, autosomal dominant would show the trait in every generation, X-linked recessive would more often affect males with carrier mothers, and mitochondrial inheritance would pass from mother to all her children. Because PRA commonly follows the two-mutant-allele pattern with carrier parents and affected offspring, autosomal recessive is the best fit.