ABCD syndrome

ABCD syndrome is an extremely rare genetic disorder whose name is an acronym for its cardinal features: Albinism, Black lock of hair, Cell migration disorder of the neurocytes of the gut (Hirschsprung disease), and Deafness (sensorineural hearing loss). This condition is now generally considered to be a variant of Waardenburg-Shah syndrome (Waardenburg syndrome type 4), which combines features of Waardenburg syndrome (pigmentary abnormalities and sensorineural deafness) with Hirschsprung disease (aganglionic megacolon). The syndrome affects multiple body systems including the skin and hair (pigmentation abnormalities including generalized albinism with a distinctive black lock of hair), the inner ear (causing congenital sensorineural hearing loss), and the enteric nervous system (resulting in absence of ganglion cells in the colon, leading to functional intestinal obstruction). ABCD syndrome is caused by mutations in the EDNRB gene (endothelin receptor type B), which plays a critical role in the development of neural crest-derived cells, including melanocytes and enteric neurons. The condition presents at birth or in the neonatal period, with Hirschsprung disease often requiring urgent surgical intervention. Affected infants may present with abdominal distension, failure to pass meconium, and constipation due to the aganglionic segment of the colon. Management is multidisciplinary and includes surgical correction of Hirschsprung disease (typically a pull-through procedure), hearing aids or cochlear implants for sensorineural hearing loss, and dermatologic monitoring for pigmentary abnormalities. There is no cure for the underlying genetic condition, and treatment remains supportive and symptom-directed. Only a very small number of cases have been reported in the medical literature.

Common questions about ABCD syndrome