1. Late-onset ptosis and myopathy in a patient with a heterozygous insertion in POLG2
- Author
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Stefanie Bulst, Joanna Stewart, Patrick F. Chinnery, Gavin Hudson, Birgit Czermin, Hanns Lochmüller, Maggie C. Walter, Solvig Müller-Ziermann, Angela Abicht, Peter Schneiderat, Elke Holinski-Feder, Thomas Klopstock, and Rita Horvath
- Subjects
Pathology ,medicine.medical_specialty ,Molecular Sequence Data ,Respiratory chain ,DNA-Directed DNA Polymerase ,Exercise intolerance ,Biology ,Exon ,Ptosis ,Mitochondrial myopathy ,Germany ,medicine ,Blepharoptosis ,Humans ,Genetic Predisposition to Disease ,Myopathy ,Cells, Cultured ,Southern blot ,Base Sequence ,Genetic Carrier Screening ,Mitochondrial Myopathies ,Muscle weakness ,Middle Aged ,medicine.disease ,Pedigree ,Mutagenesis, Insertional ,Neurology ,Female ,Neurology (clinical) ,medicine.symptom - Abstract
Polymerase gamma 1 (POLG) mutations are a frequent cause of both autosomal dominant and recessive complex neurological phenotypes. In contrast, only a single pathogenic mutation in one patient was reported in POLG2 so far. Here we describe a 62-year-old woman, carrying a novel heterozygous sequence variant in the POLG2 gene. She developed bilateral ptosis at 30 years of age, followed by exercise intolerance, muscle weakness and mild CK increase in her late forties. Muscle histology and respiratory chain activities were normal. Southern blot and long range PCR detected multiple mtDNA deletions, but no depletion in muscle DNA. Sequencing of POLG, PEO1, ANT1, OPA1 and RRM2B showed normal results. A novel heteroallelic 24 bp insertion (c.1207_1208ins24) was detected in POLG2. This 24 bp insertion into exon 7 causes missplicing and loss of exon 7 in myoblast cDNA. We did not detect POLG2 mutations in 62 patients with multiple mtDNA deletions in muscle DNA, suggesting that POLG2 mutations may represent a rare cause of autosomal dominant PEO.
- Published
- 2010
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