The type of mutation that leads to replacement of Valine for glutamate in Sickle Cell Disease is
**Core Concept**
Sickle Cell Disease is an autosomal recessive disorder caused by a mutation in the HBB gene, leading to the production of abnormal hemoglobin (HbS). This mutation results in the substitution of a hydrophobic amino acid (Valine) for a hydrophilic amino acid (Glutamate) at the sixth position of the beta-globin chain.
**Why the Correct Answer is Right**
The mutation in sickle cell disease is a point mutation that occurs in the HBB gene, resulting in the substitution of Valine (encoded by the codon GTG) for Glutamate (encoded by the codon GAG) at position 6 of the beta-globin chain. This substitution is due to a change in a single nucleotide from A to T in the HBB gene, leading to a change in the amino acid sequence of the hemoglobin protein.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the type of mutation that leads to sickle cell disease.
* **Option B:** This option is incorrect because it does not specify the type of mutation that leads to sickle cell disease.
* **Option D:** This option is incorrect because it is not a type of mutation that leads to sickle cell disease.
**Clinical Pearl / High-Yield Fact**
Sickle cell disease is caused by a single nucleotide substitution in the HBB gene, leading to a change in the amino acid sequence of the hemoglobin protein. This substitution results in the production of abnormal hemoglobin (HbS) that polymerizes under low oxygen conditions, leading to the characteristic sickling of red blood cells.
**Correct Answer: C. Point mutation**