Webb-Dattani syndrome in a 17-year-old girl.

Summary: Webb-Dattani syndrome (WEDAS) is an extremely rare autosomal recessive disorder caused by pathogenic variants in the ARNT2 gene. It is characterized by a triad of congenital hypopituitarism, structural brain abnormalities, and multisystem developmental defects. We report the case of a 17-year-old girl with WEDAS who presented with global developmental delay, panhypopituitarism, and arginine vasopressin (AVP) deficiency, formerly known as central diabetes insipidus with adipsia, visual impairment, renal anomalies, and spastic quadriplegia. Her endocrine profile revealed deficiencies in ACTH, TSH, and ADH, and gonadotropins, with a possible growth hormone deficiency. Management included hormone replacement with hydrocortisone, levothyroxine, and desmopressin, as well as fluid regulation and supportive care. Despite multiple hospitalizations due to complications including hypernatremia and infections, the patient survived into adolescence - the longest reported survival in this condition to date - before passing away at age 17. This case expands the known clinical phenotype of WEDAS, emphasizing the importance of early recognition, genetic testing, and a multidisciplinary approach to care for affected individuals, particularly in consanguineous populations where the syndrome may be underdiagnosed. Learning points: Webb-Dattani syndrome (WEDAS) is a rare autosomal recessive disorder caused by an ARNT2 pathogenic variant, presenting with a triad of congenital hypopituitarism, structural brain anomalies, and developmental delay. Adipsic diabetes insipidus is a hallmark complication in WEDAS and requires vigilant fluid management due to the absence of thirst sensation and persistent hypernatremia. Multisystem involvement - including renal anomalies and neurogenic bladder - may occur, expanding the known phenotypic spectrum of ARNT2-related disorders. Early recognition and genetic testing are essential for accurate diagnosis, especially in patients from consanguineous backgrounds presenting with multiple pituitary hormone deficiencies. Long-term survival, although rare, is possible with coordinated multidisciplinary care addressing endocrine, neurological, renal, and infectious complications. This case underscores the importance of individualized endocrine replacement therapy and caregiver education in managing complex syndromic conditions such as WEDAS.