G6PD deficiency is inherited in which pattern?

G6PD deficiency is inherited in which pattern?

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

Answer: (C)

X-linked recessive inheritance means the gene is on the X chromosome and males are more often affected because they have only one X copy. The G6PD gene resides on the X chromosome, so a single mutated copy in a male’s red blood cells is enough to cause enzyme deficiency and hemolysis under oxidative stress. Females usually have two X chromosomes, so a single mutated copy often doesn’t produce symptoms because the other X provides normal enzyme activity; only when two copies are mutated or when X-inactivation is skewed can a female show the phenotype. This pattern explains why G6PD deficiency is more common in males and can be transmitted through carrier mothers to their sons, or appear in maternal relatives. The other patterns—autosomal dominant, autosomal recessive, or X-linked dominant—don’t fit because they would produce different sex distributions and transmission checks than is typically seen with G6PD deficiency.

X-linked recessive inheritance means the gene is on the X chromosome and males are more often affected because they have only one X copy. The G6PD gene resides on the X chromosome, so a single mutated copy in a male’s red blood cells is enough to cause enzyme deficiency and hemolysis under oxidative stress. Females usually have two X chromosomes, so a single mutated copy often doesn’t produce symptoms because the other X provides normal enzyme activity; only when two copies are mutated or when X-inactivation is skewed can a female show the phenotype. This pattern explains why G6PD deficiency is more common in males and can be transmitted through carrier mothers to their sons, or appear in maternal relatives. The other patterns—autosomal dominant, autosomal recessive, or X-linked dominant—don’t fit because they would produce different sex distributions and transmission checks than is typically seen with G6PD deficiency.