The co-segregation of the MYL2 R58Q mutation in Chinese hypertrophic cardiomyopathy family and its pathological effect on cardiomyopathy disarray.

Hypertrophic cardiomyopathy (HCM), a major cause of sudden death in youth, is largely affected by genetic factors. The R58Q mutation in the MYL2 gene was identified in some HCM patients and was considered as a deleterious HCM mutation. However, the passing of R58Q between generations along with HCM symptoms was observed only in small families with only two or three members; thus, whether R58Q is as deleterious as previously claimed remains questionable. Here, we reported a large four-generation Chinese family, and found that R58Q existed in all six members with HCM and two healthy juveniles who had not yet developed HCM yet, and presumably in three deceased members who suffered from sudden death. In addition, we also found that compared with other mutations, R58Q had a more severe effect on the cellular level. Therefore, we confirmed that R58Q could be passed from generation to generation along with HCM symptoms and that it was indeed a deleterious mutation for HCM. However, further study is needed to identify additional factors that may determine the various symptoms shown in different family members within the same family.