Molecular analysis of AVPR2 gene in a Japanese patient with X-linked nephrogenic diabetes insipidus, congenital heart disease and mental retardation

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X-linked nephrogenic diabetes insipidus (NDI) is a rare disease with defective responses of renal and extrarenal arginine-vasopressin V2 receptors (AVPR2).
This is caused by mutations in the AVPR2 gene located in chromosome region Xq28. We experienced a 35-year-old male patient with NDI accompanied by severe congenital heart disease (CHD), double-outlet right ventricle (DORV), ventricular septal defect and pulmonary hypertension, as well as mental retardation. DORV is a rare CHD, and patients with such a CHD often die during childhood without surgical treatment. There have been no reports of NDI accompanied with such a severe CHD. We observed clinically and performed a genetic analysis on this patient. A missense mutation (R202C) in the AVPR2 gene from the patient was identified. One of the reasons why this patient has been able to survive so long without surgical intervention may be the reduced cardiac preload due to polyuria of NDI as well as diuretics used.