title: An unusual case of autonomous hyperparathyroidism in a patient with X-linked hypophosphatemic rickets and Kallmann syndrome.
abstract: We are reporting an unusual patient who presented to our medical center at 18 years of age for evaluation of disabling bilateral lower extremity deformity and delayed puberty. Extensive clinical, laboratory, and radiologic evaluation confirmed the coexistence of 2 X-linked inherited disorders, X-linked hypophosphatemic rickets (XLH) and Kallmann syndrome (KS). Treatment with oral phosphate and calcitriol along with intramuscular testosterone injections was initiated. Despite a dramatic response, the course of treatment was complicated by secondary hyperparathyroidism and, 13 years later, by the development of an autonomous parathyroid adenoma that was surgically resected. Furthermore, the coexistence of XLH and KS has not been reported before. We believe that the proximity of the KAL-1 gene (Xp 22.3), involved in the pathogenesis of KS, to the phosphate regulating endopeptidase on the X chromosome gene (Xp 22.1-22.2), involved in XLH, might be responsible for this association.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Lara Al-Khoury
authors.initials: LA
authors.lastname: Nabbout
authors.forename: Ibrahim S
authors.initials: IS
authors.lastname: Salti
authors.forename: Mahmoud K
authors.initials: MK
authors.lastname: Choucair
mesh_terms: D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D002118:Calcium / Q000097:blood; D053098:Familial Hypophosphatemic Rickets / Q000097:blood / Q000150:complications* / Q000235:genetics; D040181:Genetic Diseases, X-Linked; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000209:etiology*; D017436:Kallmann Syndrome / Q000097:blood / Q000150:complications* / Q000235:genetics; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000008:administration & dosage / Q000009:adverse effects; D010758:Phosphorus / Q000097:blood; D013997:Time Factors
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates; D010758:Phosphorus; D000469:Alkaline Phosphatase; D002118:Calcium