Deficiency of which of the following may cause bone deformation :

Options

A. PTH
B. Vitamin D
C. STH
D. Thyroxine

Answer

To determine which deficiency may cause bone deformation, we can analyze the options provided:

1. **PTH (Parathyroid Hormone)**: This hormone is responsible for regulating calcium levels in the blood. It increases calcium levels by stimulating the release of calcium from bones, but a deficiency in PTH would not directly cause bone deformation.

2. **Vitamin D**: This vitamin is crucial for the absorption of calcium and phosphate in the body. A deficiency in Vitamin D can lead to a condition known as Rickets in children or Osteomalacia in adults, both of which result in softening and weakening of bones, leading to bone deformation.

3. **ASTH (Somatotropin or Growth Hormone)**: This hormone is primarily responsible for growth and development. While it plays a role in bone growth, its deficiency does not specifically lead to bone deformation.

4. **Thyroxin**: This hormone regulates metabolism and energy levels in the body. A deficiency in thyroxin can lead to various metabolic issues but is not directly linked to bone deformation.

Based on this analysis, the deficiency that may cause bone deformation is **Vitamin D**.

### Step-by-Step Solution:
1. **Identify the hormones and their functions**: Review the roles of PTH, Vitamin D, ASTH, and Thyroxin.
2. **Analyze the effects of deficiencies**: Consider what happens when each hormone is deficient.
3. **Focus on bone health**: Understand how each hormone affects bone structure and strength.
4. **Conclude with the correct answer**: Identify that Vitamin D deficiency leads to conditions like Rickets, which causes bone deformation.