HYPOPHOSPHATEMIC VITAMIN-D-RESISTANT RICKETS, PRECOCIOUS PUBERTY, ANDTHE EPIDERMAL NEVUS SYNDROME

Background: The association of multisystem pathologic conditions and e pidermal nevi, known as the epidermal nevus syndrome, includes disorde rs of bone, central nervous system, eye, kidney, vasculature, body 'sy mmetry, and skin. Rarely, vitamin D-resistant rickets has been observe d in association with this syndrome. Precocious puberty is another rar e finding associated with epidermal nevus syndrome, having been observ ed in 3 patients. Observation: A female infant with an extensive epide rmal nevus, hypophosphatemia, and precocious puberty is described. Des pite medical therapy, the patient's phosphate levels continued to be v ery low (0.87-0.97 mmol/L), establishing the diagnosis of hypophosphat emic vitamin D-resistant rickets. At 21 months of age, areas of the ne vus were excised. Laboratory values obtained shortly after the operati on showed a significant, but transient, improvement in the serum phosp hate level. After a second excision, maintenance of her serum phosphat e level in the range of 1.29 to 1.61 mmol/L was possible. Conclusions: These is evidence that epidermal nevi produce a potent phosphaturic f actor. We hypothesize that limited excision debulked the nevus suffici ently to allow medical management of the hypophosphatemia. Surgical in tervention should be considered for patients affected with vitamin D-r esistant rickets with epidermal nevi. The cause of the precocious pube rty is unknown. It may be hypothesized that the nevus released a facto r that induced puberty.