What is the inheritance pattern most commonly associated with hereditary spherocytosis?

What is the inheritance pattern most commonly associated with hereditary spherocytosis?

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

Answer: (B)

Hereditary spherocytosis is most commonly autosomal dominant. A single mutated allele in genes encoding red cell membrane–cytoskeleton proteins—such as ankyrin-1, spectrin, band 3, or protein 4.2—can disrupt the link between the membrane and the cytoskeleton, making the membrane unstable and yielding spherocytes. This defect often shows up in multiple generations, even when the other allele is normal, which is characteristic of a dominant pattern. In contrast, autosomal recessive inheritance would require both copies of the gene to be mutated, which is less typical for this condition. X‑linked recessive inheritance would mostly affect males and is not a common pattern for hereditary spherocytosis. Mitochondrial inheritance doesn’t fit here either, since red blood cells lack mitochondria and the trait is transmitted through the nuclear genome.

Hereditary spherocytosis is most commonly autosomal dominant. A single mutated allele in genes encoding red cell membrane–cytoskeleton proteins—such as ankyrin-1, spectrin, band 3, or protein 4.2—can disrupt the link between the membrane and the cytoskeleton, making the membrane unstable and yielding spherocytes. This defect often shows up in multiple generations, even when the other allele is normal, which is characteristic of a dominant pattern.

In contrast, autosomal recessive inheritance would require both copies of the gene to be mutated, which is less typical for this condition. X‑linked recessive inheritance would mostly affect males and is not a common pattern for hereditary spherocytosis. Mitochondrial inheritance doesn’t fit here either, since red blood cells lack mitochondria and the trait is transmitted through the nuclear genome.