Select odd one out w.r.t. autosomal recessive trait.

Options

A. Cystic fibrosis
B. PKU
C. Sickle cell anaemia
D. Colour blindness

Answer

To solve the question of selecting the odd one out with respect to autosomal recessive traits, we will analyze each option provided:

1. **Cystic Fibrosis**:
- Cystic fibrosis is a genetic disorder that affects the lungs and digestive system. It is caused by mutations in the CFTR gene and is inherited in an autosomal recessive manner. Therefore, it is a valid example of an autosomal recessive trait.

2. **Phenylketonuria (PKU)**:
- PKU is a metabolic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase. It is also inherited in an autosomal recessive manner. Thus, PKU is another example of an autosomal recessive trait.

3. **Sickle Cell Anemia**:
- Sickle cell anemia is a blood disorder characterized by the production of abnormal hemoglobin, leading to distorted (sickle-shaped) red blood cells. This condition is also inherited in an autosomal recessive manner, making it a valid example of an autosomal recessive trait.

4. **Color Blindness**:
- Color blindness is a condition that affects the ability to distinguish colors. It is primarily inherited in an X-linked recessive manner, particularly affecting males. Therefore, color blindness does not fit the criteria of an autosomal recessive trait.

**Conclusion**:
The odd one out with respect to autosomal recessive traits is **Color Blindness** because it is inherited in an X-linked recessive manner, while the others (Cystic Fibrosis, PKU, and Sickle Cell Anemia) are all autosomal recessive traits.