Answer : Poor osteoclast function due to a carbonic anhydrase | 🎯MCQs For Medical Students🎯

Answer : Poor osteoclast function due to a carbonic anhydrase II mutation

An Acidic environment is needed for osteoclasts to remove calcium from bone. A defect in maintaining this acidic environment, leads to poor bone resorption by osteoclasts resulting in overgrowth and sclerosis of cortical bone. This abnormally thick bone fractures easily.
Clinical features include bone fractures, anaemia, thrombocytopenia (due to bony replacement of marrow) and visual/ hearing loss due to cranial nerve compression. The patient can also develop renal tubular acidosis (defect in carbonic anhydrase leads to decreased reabsorption of bicarbonate) and hydrocephalus (narrowing of foramen magnum).