A novel FAM20C mutation causing hypophosphatemic osteomalacia with osteosclerosis (mild Raine syndrome) in an elderly man with spontaneous osteonecrosis of the knee.
Our results demonstrate that mutations in FAM20C provide a putative new mechanism in human subjects leading to dysregulated FGF23 levels, hypophosphatemia, hyperphosphaturia, dental anomalies, intracerebral calcifications and osteosclerosis of the long bones in the absence of rickets.
Raine syndrome is an autosomal recessive disorder caused by mutations in the FAM20C gene that is characterized by generalized osteosclerosis with periosteal new bone formation and distinctive craniofacial dysmorphism.