BACKGROUND/PURPOSE: Patients with zinc finger homeo box 1B (ZFHX1B) mutations or 
deletions develop multiple congenital anomalies including Hirschsprung disease, 
known as Mowat-Wilson syndrome (MWS). In this study, we investigated variations 
in the enteric neural plexus abnormalities in MWS using morphometry-based 
histopathologic analysis.
METHODS: Seven patients with MWS (3 with mutations in exon 8 of ZFHX1B and 4 
with deletions) who had undergone modified Duhamel's operations for Hirschsprung 
disease were examined. Surgically resected rectosigmoid specimens were analyzed 
morphometrically.
RESULTS: The length of the aganglionic segment was longer than 3 cm in all the 
patients with deletions. In 3 patients with mutations, the aganglionic region 
was not detected in the surgically resected specimens; however, the parameters 
of the ganglions and plexus were significantly smaller than those of controls 
(cloaca and aproctia), indicative of a transitional zone. Variation in the 
severity of pathological changes among the 3 patients with mutations was also 
noted.
CONCLUSIONS: The variations in myenteric plexus pathologies in MWS appear to be 
caused by both variations in ZFHX1B abnormalities and epigenetic factors.