Thalassemia shows which kind of inheritance ?
**Core Concept**
Thalassemia is a genetic disorder that affects the production of hemoglobin, a protein in red blood cells that carries oxygen. The underlying principle being tested is the mode of inheritance of thalassemia, which is related to **autosomal recessive** traits.
**Why the Correct Answer is Right**
Thalassemia is inherited in an **autosomal recessive** pattern, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the severe form of the disease. Carriers, who have one normal and one mutated gene, typically have mild symptoms or none at all.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because thalassemia does not follow an autosomal dominant pattern, where only one copy of the mutated gene is needed to cause the disease.
**Option B:** This option is incorrect because thalassemia is not linked to the X chromosome, which would characterize X-linked inheritance.
**Option C:** This option is incorrect as it does not apply to the known inheritance pattern of thalassemia.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **autosomal recessive** disorders like thalassemia have a higher incidence in populations where consanguineous marriages are common, due to the increased chance of both parents being carriers of the same mutated gene.
**Correct Answer:** D. Autosomal Recessive.