PURPOSE: Familial neurohypophysial diabetes insipidus (FNDI), commonly caused by autosomal dominant arginine vasopressin (AVP) mutations, is a rare condition in which vasopressin fails in regulating body's level of water with final polyuria and polydipsia. Genetic testing in familial cases of FNDI should be carry out to ensure adequate treatments and avoid disease manifestations especially in infants. METHODS: In this study, we investigated three-generations of a large Italian family with clinical diagnosis of familial central diabetes insipidus for the presence of potential pathogenic mutations in the AVP gene. RESULTS: We identified a heterozygous missense mutation (c.154 T > A; p.C52S) in AVP gene in all affected members studied of a large Italian family. In silico tools were used to investigate the pathogenic role of the mutation and three-dimensional protein structure predicted that the p.C52S impairs disulfide bridges formation resulting in misfolding of the protein. CONCLUSIONS: This is the first study that identified a novel missense p.C52S mutation as causative of central diabetes insipidus in a large Italian pedigree.