OBSOLETE: Hypertrichotic osteochondrodysplasia

Hypertrichotic osteochondrodysplasia, also known as Cantu syndrome, is a rare genetic disorder characterized by the combination of excessive hair growth (hypertrichosis), skeletal abnormalities (osteochondrodysplasia), and cardiac defects. This entry in Orphanet (ORPHA:2765) is now classified as obsolete, as the condition has been reclassified and is currently referenced under Cantu syndrome (ORPHA:1517). The disease primarily affects the skeletal, cardiovascular, and integumentary (skin and hair) systems. Key clinical features include generalized hypertrichosis present from birth, a characteristic facial appearance with coarse features, macrosomia (large body size), skeletal anomalies such as thickened calvaria and broad ribs, and congenital heart defects including patent ductus arteriosus and cardiomegaly. The condition is caused by gain-of-function mutations in the ABCC9 or KCNJ8 genes, which encode subunits of ATP-sensitive potassium channels. These channels play important roles in vascular smooth muscle and cardiac tissue. Management is primarily supportive and symptom-based, involving cardiac monitoring and surgical intervention for significant heart defects when necessary. Minoxidil-like effects of the channel dysfunction explain the hypertrichosis and cardiovascular features. Research into targeted potassium channel inhibitors such as glibenclamide is ongoing as a potential disease-specific therapy. Patients are advised to seek care from a multidisciplinary team including cardiologists, geneticists, and orthopedic specialists.

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