Background Myosin storage myopathy (MSM) is caused by missense mutations in the MYH7 gene, which encodes the β-cardiac/slow skeletal muscle myosin heavy chain rod (MyHCI). MSM is an autosomal dominant/recessive myopathy characterized by subsarcolemmal accumulations of myosin in type I muscle fibers that results in weakness of the scapula, limb and distal muscles.Methods Here, we report a MSM phenotype that was present across three generations of individuals from the same family, one of whom was a neonate.Results At birth, the neonate had an elevated creatine kinase level and decreased muscle tone in the limbs. At 2 months of age, the infant’s cervical vertebrae caused his head to be skewed to the right. At 7 months of age, the infant’s development was delayed.Whole exome sequencing showed a novel heterozygous variant NM_000257.3: c.3830G>A (p.Arg1277Gln) at exon 28 of the MYH7 gene in the DNA of the infant and his father.Conclusions Previously, which site has only been reported in 2 cases of cardiomyopathy; therefore, this study expands our knowledge of the clinical phenotypes associated with mutations within the rod region of MyHCI. Importantly, close follow-up of the neonate will provide important information on the natural history of MSM associated with MYH7 gene mutation.

No abstract