Early Death of 2 Siblings Related to Mutations in LMOD2, a Recently Discovered Cause of Neonatal Dilated Cardiomyopathy.

We report a family with 2 neonatal deaths related to dilated cardiomyopathy (DCM) and compound heterozygous loss-of-function variants (c.1243_1244del, p.Leu415Valfs*108 and c.1537C > T, p.Arg513*) in Leiomodin 2 (LMOD2), a recently documented cause of early DCM. The phenotype in mice and humans consists of early, severe cardiac dilation and dysfunction related to decreased functional LMOD2, which results in abnormal actin filaments and abnormal myocardial contractility. Our cases confirm mutations in LMOD2 as a cause of DCM in humans and highlight the rapid changes occurring in cardiac genetics and the importance of reviewing previously negative genetic test results in the context of emerging literature.