Which type of inheritance is Sickle Cell Disease associated with?

• A. Autosomal Dominant
• B. Autosomal Recessive
• C. Chromosomal Disorder
• D. X-Linked Dominant

Answer: (B)

Sickle Cell Disease is associated with autosomal recessive inheritance, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to express the disease. This condition arises from a mutation in the HBB gene, which encodes the beta-globin subunit of hemoglobin. When a person inherits one normal allele and one mutated allele, they are carriers of the disease (known as having sickle cell trait) but typically do not experience the symptoms associated with Sickle Cell Disease. It is only when the individual inherits the mutated gene from both parents that the phenotype associated with the disease manifests, resulting in the characteristic sickle-shaped red blood cells, which can lead to various complications.

In contrast to this, other inheritance types mentioned do not apply to Sickle Cell Disease: autosomal dominant inheritance requires only one copy of the mutated gene to express the condition; chromosomal disorders involve structural or numerical abnormalities of chromosomes; and X-linked dominant inheritance refers to traits linked to genes on the X chromosome, which Sickle Cell Disease is not. Thus, the classification as autosomal recessive is central to understanding how Sickle Cell Disease is inherited and expressed in the population.