Congenital nephrogenic diabetes insipidus with a novel variant of AVPR2 gene mutation: A case report

Congenital nephrogenic diabetes insipidus (CNDI) is a rare genetic disorder characterized by impaired water reabsorption despite normal or elevated levels of antidiuretic hormone. We report a 6-month-old male with classical symptoms of CNDI, such as fever, excessive thirst, polyuria, and failure to thrive. Laboratory investigations revealed hypernatremia, low urine osmolality, and a lack of response to a vasopressin challenge, confirming the diagnosis. Genetic testing identified a hemizygous base pair deletion in the AVPR2 gene, leading to a frameshift mutation and premature protein truncation. Treatment strategies, including hydrochlorothiazide and amiloride therapy, aim to manage symptoms and improve quality of life. Long-term management involves monitoring growth, hydration status, and genetic counseling for affected families. This case highlights the importance of early recognition and management of CNDI to prevent long-term sequelae. Further research into genetic variations and novel therapeutic approaches is warranted to improve outcomes for these children.