Unusual Association of Hypophosphatemic Richets

D. BRASLAVSKY; H. CASSINELLI; G. DEL REY; L. GRUÑEIRO

Mar del Plata, Argentina

Congreso; SOCIEDAD LATINO-AMERICANA DE ENDOCRIONLOGÍA PEDIÁTRICA; 2007

SOCIEDAD LATINO-AMERICANA DE ENDOCRIONLOGÍA PEDIÁTRICA

X-linked hypophosphatemia (XLH) is the most prevalent heritable form of rickets. It is characterized by renal phosphate wasting, and a defective bone mineralization. On the other hand, the 46 XX male syndrome represents a rare, and poorly characterized form of male hypogonadism. We report the rare association of an adolescent with XLH and hypergonadotrophic hipogonadism. We present a boy with diagnosis of XLH made at the first year of age, in which his mother and brother have the same pathology. Basal laboratory showed phosphorus 2.5 mg/dl («), AP 1115 U/L (ª), PTR 15% («), and radiological features of rickets. Normal FGF23. He started treatment with Calcitriol and Neutraphos-K. A total regression of rickets was obtained. The dose was adapted according to his growth. At the age of 12.2 years old, he began his puberty G2, PH2, T4/4 ml, reaching, at the age of 13.8 years old, G4, PH4, T10/10. But, 8 months later, gynecomastia is noted B3-2, PH4, G4 and testicular volume of 5/5ml. Laboratory: LH 20 mUI/ml(ª), FSH 71.8 mUI/ml(ª), AMH 4 pmol/l, Testosterone 213 ng/dl(«), Karyotype: 46XX, ish(Y)(SRY+), ish(X)(DXZ1++). Although XLH rickets is frequent, either in female as male, the 46 XX male syndrome is not a frequent form of hypogonadism. In spite of both pathologies involve the X sexual chromosomes, they do not have a relation in common. By an abnormal paternal meiotic recombination the SRY was translocated in the X chromosome. The association of XLH and 46 XX male syndrome has not been described up to date.