Introduction: Nemaline myopathy (NM) is a congenital neuromuscular disorder often characterized by hypotonia, facial weakness, skeletal muscle weakness, and the presence of rods on muscle biopsy. A rare form of nemaline myopathy known as Amish Nemaline Myopathy has only been seen in a genetically isolated cohort of Old Order Amish patients who may additionally present with tremors in the first 2-3 months of life.
Methods: We describe an Hispanic male diagnosed with nemaline myopathy histopathologically and subsequently confirmed by next generation gene sequencing.
Results: Direct sequencing revealed that he is homozygous for a pathogenic nonsense variant c.323C>G (p.S108X) in exon 9 of the TNNT1 gene.
Conclusions: This report describes a novel pathogenic variant in the TNNT1 gene and represents a nemaline myopathy-causing variant in the TNNT1 gene outside of the Old Order Amish and Dutch ancestry.
Keywords: Amish nemaline myopathy (ANM); TNNT1; congenital myopathy; nemaline myopathy; slow skeletal muscle troponin T1.
© 2014 Wiley Periodicals, Inc.