Question

Select the correct match with respect to the disorders and the chromosome in which the mutation responsible for the disorder occurs.

• A. Alpha thalassemia→ chromosome 11
• B. Beta thalassemia→ chromosome 16
• C. Sickle cell anaemia→ chromosome 12
• D. Phenylketonuria→ chromosome 12

Answer 1

The correct option is D Phenylketonuria→ chromosome 12

The diseases mentioned above are autosomal linked recessive diseases. These diseases are caused due to mutations in genes located on specific autosomes.
Phenylketonuria is caused due to mutation of both alleles of the gene encoding an enzyme phenylalanine hydroxylase. This gene is located on chromosome 12.
Thalassemia is caused due to mutations in gene encoding globin chains of haemoglobin. Haemoglobin is made up of two globin chains- alpha-globin chain and beta-globin chain. There are two copies of the hemoglobin alpha gene (HBA-1 and HBA-2), which each encode an α-chain, and both genes are located on chromosome 16. The gene encoding beta-globin chain is on chromosome 11. Faulty synthesis of the alpha-globin chain leads to alpha thalassemia, and that of the beta-globin chain results in beta-thalassemia.
Sickle cell anaemia is caused due to a different mutation in the gene encoding the beta-globin chain on chromosome 11.
Hence, option d is correct.