Neuronal Intestinal Dysplasia, Type B

As pointed out by Barone et al. (1996), Fadda et al. (1983) differentiated 2 clinical and histochemical forms of neuronal intestinal dysplasia, NID A (see 243180) and NID B. NID A is a very rare condition characterized by congenital hypoplasia or aplasia of the sympathetic innervation of the intestine. In NID B, the entity discussed in this entry, the parasympathetic submucous plexus is primarily affected. As indicated by Borchard et al. (1991), characteristic histologic and histochemical findings, on which the diagnosis can be based, are (1) hyperplasia of submucosal plexuses with giant submucosal ganglia, (2) increased acetylcholinesterase activity in nerve fibers around submucosal blood vessels, (3) increased acetylcholinesterase activity in nerve fibers of the lamina propria mucosae, and (4) heterotopic ganglion cells in the lamina propria mucosae and in the muscularis mucosae. While most cases of NID B are sporadic, the observation of the few familial clusters suggest autosomal dominant inheritance (Scharli (1992)). The frequency of NID B is difficult to estimate because of high variability of the clinical expression and difficulties in making the diagnosis (Martucciello et al., 1994).

Barone et al. (1996) analyzed 2 NID B families for linkage to the RET locus (164761) on 10q, which is the site of mutations in Hirschsprung disease (142623), another form of intestinal dysganglionosis. Linkage to RET was excluded.