Congenital fibre type disproportion associated with mutations in the tropomyosin 3 (TPM3) gene mimicking congenital myasthenia.
Article Details
- CitationCopy to clipboard
Munot P, Lashley D, Jungbluth H, Feng L, Pitt M, Robb SA, Palace J, Jayawant S, Kennet R, Beeson D, Cullup T, Abbs S, Laing N, Sewry C, Muntoni F
Congenital fibre type disproportion associated with mutations in the tropomyosin 3 (TPM3) gene mimicking congenital myasthenia.
Neuromuscul Disord. 2010 Dec;20(12):796-800. doi: 10.1016/j.nmd.2010.07.274. Epub 2010 Oct 14.
- PubMed ID
- 20951040 [ View in PubMed]
- Abstract
Congenital myopathy with fibre type disproportion (CFTD) has been associated with mutations in ACTA1, SEPN1, RYR1 and TPM3 genes. We report the clinico-pathological and electrophysiological features of 2 unrelated cases with heterozygous TPM3 mutation. Case 1 is a 19-year-old lady who presented with motor delay in infancy, respiratory failure in early teens requiring non-invasive ventilation despite being ambulant, ptosis, axial more than proximal weakness and scoliosis. Case 2 is a 7-year-old boy with hypotonia, feeding difficulties, motor delay and scoliosis, also requiring non-invasive ventilation while ambulant. Muscle biopsies in both cases showed fibre type disproportion. Muscle MRI (Case 1) showed mild uniformly increased interstitial tissue in and around the muscles. Sequencing of TPM3 in case 1 revealed a previously described heterozygous c.503G > A(pArg168His) missense variant in exon 5 and a novel heterozygous missense mutation c.521A > C(pGlu174Ala), also in exon 5, in case 2. A mild abnormality in the single fibre EMG was documented on electrophysiology in both cases. These cases highlight the neuromuscular transmission defect in CFTD secondary to TPM3 mutations.