Familial central or neurohypophyseal diabetes insipidus (FNDI) results from insufficient production of antidiuretic hormone arginine vasopressin, which is caused by mutations in arginine vasopressin-neurophysin II gene (AVP-NPII). In this study, we present the clinical features of a male Turkish patient with autosomal dominant neurohypophyseal DI caused by a novel mutation (p.E108D). The prospective clinical data were collected for the proband patient and his family members. The patient had severe polyuria (10.9 l/day), polydipsia (12 l/day), fatique, and deep thirstiness from his infancy. While being performed water deprivation test, diagnosis of central diabetes insipidus was confirmed according to increase in urine osmolality from 139 to 431 mOsm/kg after desmopressin acetate injection. Some of family members of this patient had severe polyuria, nocturia, polydipsia, fatigue as well. The genomic DNA of the proband and the other family members were isolated and the amplification of the AVP-NPII gene was carried out with polymerase chain reaction. We were sequenced all exons and intron-exon boundaries of the gene. We detected a novel heterozygous missense mutation at codon 108, which causes the the substitution of Glu (GAG) by a Asp (GAT) in exon 3. A three-dimensional protein structure prediction was shown for the mutant AVP-NPII protein and compared with the wt. In our future studies we are planning to do functional analyses studies for understanding the function of the p.E108D mutation.
28 - 31 May 2016
European Society of Endocrinology