Hirschsprung disease is a developmental disorder resulting from the arrest of 
the craniocaudal migration of enteric neurons from the neural crest along 
gastrointestinal segments of variable length; see Behrman [Nelson textbook of 
pediatrics, 1992:954-956]. It is a heterogeneous disorder in which familial 
cases map to at least three loci whose function is necessary for normal neural 
crest-derived cell development. Homozygous mutations in the endothelin-B 
receptor gene (EDNRB) on 13q22 have been identified in humans and mice with 
Hirschsprung disease type 2 (HSCR2). The auditory pigmentary disorder, 
Waardenburg-Shah syndrome, comprises Waardenburg syndrome and Hirschsprung 
disease and has also been mapped to the EDNRB locus. Hirschsprung disease, 
malrotation, isochromia, a profound sensorineural hearing loss, and several 
other anomalies were found in an infant with an interstitial deletion of 13q, 
suggesting the existence of a contiguous gene syndrome involving developmental 
genes necessary for the normal growth of the neural crest derivatives of the 
eye, inner ear, and colon. We report on an additional patient with a deletion in 
13q and Hirschsprung disease. Congenital anomalies associated with deletions of 
the distal long arm of chromosome 13 are sufficiently consistent to suggest a 
clinical syndrome.