A new article published in the Journal of Clinical Medicine stated that myosin Vb (MYO5B) is a motor protein that facilitates protein trafficking and recycling in polarized cells by RAB11- and RAB8-dependent mechanisms.

The authors informed that biallelic MYO5B mutations are identified in the majority of patients with microvillus inclusion disease (MVID). MVID – an intractable diarrhea of infantile onset, exhibits characteristic histopathologic findings that requires life-long parenteral nutrition or intestinal transplantation. A large number of such patients eventually develop cholestatic liver disease. While bi-allelic MYO5B mutations are also identified in a subset of patients with predominant early-onset cholestatic liver disease.

The present article presented a compilation of 114 patients with disease-causing MYO5B genotypes, including 44 novel patients as well as 35 novel MYO5B mutations, and an analysis of MYO5B mutations with regard to functional consequences.

The findings suggested that a complete lack of MYO5B protein or early MYO5B truncation causes predominant intestinal disease (MYO5B-MVID); the expression of full-length mutant MYO5B proteins with residual function causes predominant cholestatic liver disease (MYO5B-PFIC); and the expression of mutant MYO5B proteins without residual function causes both intestinal and hepatic disease (MYO5B-MIXED). Genotype-phenotype data are deposited in the existing open MYO5B database in order to improve disease diagnosis, prognosis and genetic counseling.

Source: Journal of Clinical Medicine. 2021 Jan 28;10(3):481. doi: 10.3390/jcm10030481.