A new homozygous missense variant in LMOD3 gene causing mild nemaline myopathy with prominent facial weakness.

• NEM type 10 is caused by bi-allelic mutations in the LMOD3 gene. • NEM type 10 is usually characterized by a severe congenital nemaline myopathy. • We report two adult patients with mild NM, due to a new missense variant in LMOD3. Nemaline myopathy (NEM) type 10, caused by biallelic mutations in LMOD3 , is a severe congenital myopathy clinically characterized by generalized hypotonia and muscle weakness, respiratory insufficiency, joint contractures, and bulbar weakness. Here, we describe a family with two adult patients presenting mild nemaline myopathy due to a novel homozygous missense variant in LMOD3. Both patients presented mild delayed motor milestones, frequent falls during infancy, prominent facial weakness and mild muscle weakness in the four limbs. Muscle biopsy showed mild myopathic changes and small nemaline bodies in a few fibers. A neuromuscular gene panel revealed a homozygous missense variant in LMOD3 that co-segregated with the disease in the family (NM_198271.4: c.1030C>T; p.Arg344Trp). The patients described here provide evidence of the phenotype-genotype correlation, suggesting that non-truncating variants in LMOD3 lead to milder phenotypes of NEM type 10. [ABSTRACT FROM AUTHOR]