Cardiomyopathy: A Systematic Review of Disease-Causing Mutations in Myosin Heavy Chain 7 and Their Phenotypic Manifestations

BACKGROUND: Mutations in myosin heavy chain 7 (MYH7) commonly cause cardiomyopathy. However, the relationship between mutation location, cardiomyopathy type, change in amino acid composition and disease severity is poorly understood. This systematic review aims to provide, on a large scale, important insights into the role mutations in MYH7 play in cardiomyopathy. METHODS: The literature was searched from 1966 to March 2009. The mutation location, type of mutation and disease type and severity were documented. When the severity of disease was known, the change in charge and hydropathy of the mutation was determined. Where appropriate, either a chi(2) test was used or a relative risk ratio was calculated in order to evaluate the data. RESULTS: The data presented in this study demonstrate that there are proportionately more mutations in the head and neck regions of this gene than in the tail. Importantly, mutations in the head of the gene, those that cause large changes in the hydropathy of the amino acid and non-conservative mutations are more likely to lead to a severe phenotype. CONCLUSIONS: This study suggests that mutation location in the MYH7 gene and changes in amino acid composition can have a negative impact on the disease outcome in individuals with cardiomyopathy.