Recessive myosin myopathy with external ophthalmoplegia associated with MYH2 mutations.

Abstract

Myosin myopathies comprise a group of inherited diseases caused by mutations in myosin heavy chain (MyHC) genes. Homozygous or compound heterozygous truncating MYH2 mutations have been demonstrated to cause recessive myopathy with ophthalmoplegia, mild-to-moderate muscle weakness and complete lack of type 2A muscle fibers. In this study, we describe for the first time the clinical and morphological characteristics of recessive myosin IIa myopathy associated with MYH2 missense mutations. Seven patients of five different families with a myopathy characterized by ophthalmoplegia and mild-to-moderate muscle weakness were investigated. Muscle biopsy was performed to study morphological changes and MyHC isoform expression. Five of the patients were homozygous for MYH2 missense mutations, one patient was compound heterozygous for a missense and a nonsense mutation and one patient was homozygous for a frame-shift MYH2 mutation. Muscle biopsy demonstrated small or absent type 2A muscle fibers and reduced or absent expression of the corresponding MyHC IIa transcript and protein. We conclude that mild muscle weakness and ophthalmoplegia in combination with muscle biopsy demonstrating small or absent type 2A muscle fibers are the hallmark of recessive myopathy associated with MYH2 mutations.

• Authors: Homa Tajsharghi, Simon Hammans, Christopher Lindberg, Alexander Lossos, Nigel F Clarke, Ingrid Mazanti, Leigh B Waddell, Yakov Fellig, Nicola Foulds, Haider Katifi, Richard Webster, Olayinka Raheem, Bjarne Udd, Zohar Argov, Anders Oldfors
• Journal: European journal of human genetics : EJHG (Eur J Hum Genet) Vol. 22 Issue 6 Pg. 801-8 (Jun 2014) ISSN: 1476-5438 [Electronic] England
• PMID: 24193343 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Codon, Nonsense
• Myosin Heavy Chains

Topics

• Adult
• Biopsy
• Child
• Codon, Nonsense
• DNA Mutational Analysis
• Family Health
• Female
• Gene Expression
• Genes, Recessive
• Genetic Predisposition to Disease (genetics)
• Humans
• Male
• Middle Aged
• Muscle Fibers, Fast-Twitch (pathology)
• Muscle Weakness (pathology)
• Muscular Diseases (genetics, pathology)
• Mutation, Missense
• Myosin Heavy Chains (genetics)
• Ophthalmoplegia (genetics, pathology)
• Pedigree
• Reverse Transcriptase Polymerase Chain Reaction