Which of the following conditions is a type of skeletal dysplasia primarily affecting endochondral ossification, leading to disproportionate short stature with normal torso length?
1) Generalized cortical hyperostosis
2) Craniofacial dystosis
3) Marfan's syndrome
4) Achondroplasia
📝 Explanation:
Achondroplasia is the most common form of short-limb dwarfism and affects endochondral bone formation (bone formation in cartilage), particularly in the long bones. This results in characteristic features like short arms and legs and an average-sized trunk.
Generalized cortical hyperostosis: This condition involves excessive thickening of the outer layer (cortex) of bones, not primarily the growth plates, and does not lead to the disproportionate short stature seen in achondroplasia.
Craniofacial dystosis: This is a condition (such as Crouzon syndrome) characterized by abnormal development of the skull and facial bones (premature fusion of cranial sutures), which can affect the shape of the head and face, but does not primarily cause the disproportionate limb shortening of achondroplasia.
Marfan's syndrome: This is a connective tissue disorder that typically causes individuals to be tall and thin with long limbs and fingers (dolichostenomelia), the opposite of the skeletal features in achondroplasi1) It commonly affects the cardiovascular and ocular systems.
MCQ