Acromesomelic dysplasia, Maroteaux type

Acromesomelic dysplasia, Maroteaux type (AMDM) is a rare inherited skeletal disorder characterized by disproportionate short stature primarily affecting the middle (mesomelic) and distal (acromelic) segments of the limbs — meaning the forearms, lower legs, hands, and feet are particularly shortened. The condition is caused by mutations in the NPR2 gene (natriuretic peptide receptor B), which plays a critical role in bone growth and endochondral ossification. Affected individuals typically appear normal at birth but develop noticeable limb shortening during early childhood. The condition is also known as acromesomelic dwarfism, Maroteaux type. Key clinical features include short forearms and lower legs, short and broad hands and feet with brachydactyly (shortened fingers and toes), and a relatively normal trunk length. Radiographic findings often reveal shortening of the radius and ulna, as well as the tibia and fibula, with characteristic vertebral abnormalities including wedge-shaped or ovoid vertebral bodies in early childhood. The head and facial features are generally normal. Adult height is typically significantly reduced, often in the range of 97–130 cm. Intelligence and cognitive development are normal. There is currently no specific cure or disease-modifying treatment for acromesomelic dysplasia, Maroteaux type. Management is supportive and symptomatic, focusing on orthopedic monitoring, physical therapy, and addressing any functional limitations. Research into C-type natriuretic peptide (CNP) analogs, such as vosoritide, which targets the same signaling pathway affected in this condition, is an area of active scientific interest, though such therapies are not yet established for AMDM. Genetic counseling is recommended for affected families.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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