Mutation in Actin γ-2 Responsible for Megacystis Microcolon Intestinal Hypoperistalsis Syndrome in Four Chinese Patients.

The aim of this study was to identify the underlying molecular mechanism for the development of megacystis microcolon intestinal hypoperistalsis syndrome in 4 Chinese patients. We found a c.770G>A (p.R257H) mutation in 3 patients, and a c.769C>T (p.R257C) mutation in the fourth patient by using whole-exome sequencing and targeted Sanger sequencing. The immunohistochemical investigation and transmission electron microscopy revealed an apparent defect of the intestinal smooth muscle, and hypoganglionosis. Our report suggested that R257 variant in the ACTG2 appear to be more frequent in populations of Asian ancestry; mutation of this locus could cause alterations of the intestinal and bladder smooth muscle filaments.