Albers Schonberg disease is also called as –
**Core Concept**
Albers-Schönberg disease, also known as marble bone disease, is a rare genetic disorder characterized by an abnormal increase in bone density due to defective osteoclast function. This condition leads to an accumulation of unresorbed bone matrix, resulting in a characteristic "marbled" appearance on radiographs.
**Why the Correct Answer is Right**
The disease is caused by mutations in the TCIRG1 gene, which encodes the enzyme carbonic anhydrase II involved in acidification of the osteoclast resorption compartment. This acidification is essential for osteoclast-mediated bone resorption. In Albers-Schönberg disease, the defective acidification impairs osteoclast function, leading to an accumulation of unresorbed bone matrix.
**Why Each Wrong Option is Incorrect**
**Option A:** **Osteopetrosis** is a related condition, but it is not the same as Albers-Schönberg disease. Osteopetrosis is characterized by an increased bone density without the characteristic "marbled" appearance of Albers-Schönberg disease.
**Option B:** **Paget's disease** is a different condition altogether, characterized by abnormal bone remodeling and an increased risk of osteosarcoma. It is not related to defective osteoclast function.
**Option C:** **Rickets** is a condition caused by vitamin D deficiency, leading to softening of the bones in children. It is not related to Albers-Schönberg disease.
**Clinical Pearl / High-Yield Fact**
Albers-Schönberg disease is a rare genetic disorder that highlights the importance of proper osteoclast function in bone remodeling. Defects in osteoclast function can lead to abnormal bone density and increased risk of fractures.
**Correct Answer:** C.