Hypophosphatemic Rickets Associated with Epidermal Nevus Syndrome and Giant Hairy Nevus

Abstract

The association of hypophosphatemic rickets and epidermal nevus or giant hairy nevus is rare. We report two patients with hypophosphatemic rickets, one associated with epidermal nevus syndrome and the other with giant hairy nevus, and describe their clinical features and variable response to treatment. The abnormal nevus tissue may have contributed to the pathogenesis of hypophosphatemic rickets. We did not find a PHEX gene mutation in these two patients, and the mechanism for their rickets may be different from that in X-linked hypophosphatemic rickets.

Cutaneous skeletal hypophosphatemia syndrome: clinical spectrum, natural history, and treatment

“…Coexistence of hypophosphatemia and focal bone lesions was observed in 26/51 subjects described in the literature [1, 7–9, 11, 12, 14, 16, 17, 19, 22, 24, 25, 27–29, 32, 35–37, 41, 42, 45, 49]. In 18/51 reports, hypophosphatemia and/or rickets was reported without mention of skeletal dysplasia, and radiographs were either not provided or did not demonstrate dysplasia [3, 11–13, 15, 18, 20, 21, 23, 26, 31, 33, 34, 38, 39, 48].…”

“…Limb deformities, predominantly bowing, were reported in 36/51 (70 %) [1, 3, 7, 9, 11–13, 15–17, 19–22, 24, 25, 27, 29–34, 37–39, 41–43, 47–49]. Scoliosis was described in 21/51 (41 %) [1, 3, 7, 9, 12–14, 16, 19, 20, 22, 24, 27, 30, 31, 34, 39–41, 44, 47, 48].…”

Linear nevus sebaceous syndrome with hypophosphatemic rickets with elevated FGF-23

“…Several cases of LNSS with the complication of severe rickets have been reported [3][4][5][8][9][10]. However, in only two patients have the serum FGF-23 levels been measured, and in both cases they were found to be high [5,6].…”

The group of epidermal nevus syndromes

“…24,71,[75][76][77] As an unusual complication, some patients with Schimmelpenning syndrome develop vitamin Deresistant hypophosphatemic rickets. 27,40,[78][79][80][81][82][83][84][85][86][87][88] In 2003, we proposed the term ''HYPHEN'' syndrome as an acronym for hypophosphatemia with epidermal nevus. 89 Today, however, we agree that this combination of anomalies can be best categorized as a clinical variant of Schimmelpenning syndrome, which is why the term HYPHEN syndrome appears to be superfluous.…”