Question

All the given disorders belong to the same set of Mendelian disorders except the one. Find the odd one out.

• A. Haemophilia
• B. Thalassemia
• C. Phenylketonuria
• D. Sickle cell anaemia

Answer 1

The correct option is B Thalassemia

Hemophilia:

Hemophilia is a group of diseases in which blood does not clot normally. Factors in blood are involved in clotting. Hemophiliacs lacking the normal factor VIII are said to have hemophilia.

Thalassemia:

It is a group of inherited blood disorder which inhibits the body's ability to produce hemoglobin and RBC.

Phenylketonuria:

It is recessively inherited disorder who suffers from lack of the ability to synthesize an enzyme to convert the amino acid phenylalanine into tyrosine.

Sickle Cell Anemia:

It is an autosomal recessive disorder. The recessive allele causes a single amino acid substitution in the beta chains of hemoglobin. When oxygen concentration is low, the sickling of cells occurs.

In the above disorders hemophilia, phenylketonuria, Sickle Cell anemia belong to the Mendelian disorders whereas Thalassemia is different. Hence, the correct answer is option B, Thalassemia.