Proteinuria, hypertension and chronic renal failure in X-linked Kallmann's syndrome, a defined genetic cause of solitary functioning kidney.

Background: Anosmia and hypogonadotrophic hypogonadism are the classic features of X-linked Kallmann's syndrome, a disorder caused by mutations of KAL, a gene expressed during kidney and brain development. About a third of patients have a solitary functioning kidney, but little is known about their renal morbidity.

Methods: We studied seven patients aged 22-35 years with X-linked Kallmann's syndrome and a solitary functioning kidney.

Results: Two patients developed significant proteinuria associated with mild to moderate arterial hypertension in the second to third decades of life. In one, proteinuria and renal impairment preceded the appearance of hypertension, and the disorder progressed to chronic renal failure. The remaining five patients had normal plasma creatinine concentrations and no significant proteinuria although four had borderline systolic and/or diastolic hypertension. In two sets of patients from the same kindreds, there was a striking discordance for the occurrence of renal morbidity.

Conclusions: All patients with X-linked Kallmann's syndrome should be screened for renal malformations, and those with solitary kidneys require life-long follow-up to detect hypertension, proteinuria and renal failure.