<scp> LMOD2 </scp> ‐related dilated cardiomyopathy presenting in late infancy

Leiomodin-2 (LMOD2) is an important regulator of the thin filament length, known to promote elongation of actin through polymerization at pointed ends. Mice with Lmod2 deficiency die around three weeks of age due to severe dilated cardiomyopathy, resulting from decreased heart contractility due to shorter thin filaments. To date, there have been three infants from two families reported with biallelic variants in LMOD2, presenting with perinatal onset dilated cardiomyopathy. Here, we describe a third family with a child harboring a previously described homozygous frameshift variant, c.1243_1244delCT (p.L415Vfs*108) with dilated cardiomyopathy, presenting later in infancy at nine months of age. Family history was relevant for a sibling who died suddenly at one year of age after being diagnosed with cardiomegaly. LMOD2-related cardiomyopathy is a rare form of inherited cardiomyopathy resulting from thin filament length dysregulation and should be considered in genetic evaluation of newborns and infants with suspected autosomal recessive inheritance or sporadic early onset cardiomyopathy.