What is the inheritance pattern of G6PD deficiency?

What is the inheritance pattern of G6PD deficiency?

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

Answer: (B)

G6PD deficiency is inherited in an X-linked recessive pattern. The G6PD gene is located on the X chromosome, so males, who have only one X, will manifest the deficiency if that single X carries the mutation. Females have two X chromosomes, so one normal copy usually suffices to maintain enough enzyme activity, making them typically carriers rather than affected. Only in rare cases—such as a female inheriting two defective X chromosomes or having skewed X‑inactivation—might she show symptoms. This pattern also explains why affected individuals are predominantly male and how the mutation can be transmitted from carrier mothers to half of their sons (who are affected) and half of their daughters (who become carriers).

G6PD deficiency is inherited in an X-linked recessive pattern. The G6PD gene is located on the X chromosome, so males, who have only one X, will manifest the deficiency if that single X carries the mutation. Females have two X chromosomes, so one normal copy usually suffices to maintain enough enzyme activity, making them typically carriers rather than affected. Only in rare cases—such as a female inheriting two defective X chromosomes or having skewed X‑inactivation—might she show symptoms. This pattern also explains why affected individuals are predominantly male and how the mutation can be transmitted from carrier mothers to half of their sons (who are affected) and half of their daughters (who become carriers).