A novel disease-causing mutation in AVPR2: Q96H.

A 4-month-old male infant was diagnosed with nephrogenic diabetes insipidus (NDI). Genetic testing of the arginine vasopressin receptor-2 (AVPR2) yielded a novel X-linked mutation, termed Q96H, in both the propositus and his mother; there was no family history. Protein sequence comparison between AVPR subtypes shows that Q96 is part of a highly conserved motif. Many other disease-causing mutations, confirmed with in vitro expression studies, map to surrounding residues. Molecular modelling studies showed that the equivalent residue in AVPR1 is likely critical for vasopressin binding. We posit that Q96 must be important for the integrity of AVPR2 function.