An unusual case of hereditary nephrogenic diabetes insipidus (HNDI) affecting mother and daughter.

We report a mother and daughter in the same family with HNDI due to a heterozygous deletion in exon 1 of the AVPR2 gene, not previously described in the literature. A 5-year-old girl was referred for investigation of polyuria and polydipsia. The patient had a water deprivation test elsewhere at the age of 3 that was inconclusive. A degree of water restriction was imposed leading to headaches. The thyroid, cortisol, renal, and calcium profiles were normal. Her mother showed similar symptoms that had not been previously investigated. AQP2 (Aquaporin) and initial AVPR2 gene sequencing had not identified a mutation, but subsequent quantitative polymerase chain reaction analysis revealed a heterozygous large exon 1 deletion of the AVPR2 gene. The same deletion was also found in the child's mother. The patient's symptoms have significantly improved on appropriate treatment. Further analysis revealed skewed X inactivation in mother and daughter. PMID: 26244674 [PubMed - as supplied by publisher]
Source: Diabetes Metab - Category: Endocrinology Authors: Tags: J Pediatr Endocrinol Metab Source Type: research