Abstract
A clinical and molecular study is reported of 83 patients considered to be minimally affected with myotonic dystrophy (DM). These had been identified in three ways: 60 subjects were identified on clinical grounds and were divided into those with and those without neuromuscular involvement (groups I and II); nine subjects were at high risk of carrying the DM gene but had a normal phenotype (group III); and 14 were parents of definitely affected patients where neither parent showed clinical abnormalities (group IV). PCR analysis of the CTG repeat in the DM gene showed a range of 70 to 230 repeats for the younger at risk patients in group III, while the asymptomatic gene carriers in group IV had 53 to 60 repeats. The sensitivity of diagnosis by EMG was found to be 39%. For ophthalmic signs this was 97.5%. This suggests that assignment on the basis of minimal clinical features carries a significant error. Molecular analysis, in conjunction with established clinical investigations, should prove valuable in the identification and exclusion of minimal myotonic dystrophy.
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- Aslanidis C., Jansen G., Amemiya C., Shutler G., Mahadevan M., Tsilfidis C., Chen C., Alleman J., Wormskamp N. G., Vooijs M. Cloning of the essential myotonic dystrophy region and mapping of the putative defect. Nature. 1992 Feb 6;355(6360):548–551. doi: 10.1038/355548a0. [DOI] [PubMed] [Google Scholar]
- Brook J. D., McCurrach M. E., Harley H. G., Buckler A. J., Church D., Aburatani H., Hunter K., Stanton V. P., Thirion J. P., Hudson T. Molecular basis of myotonic dystrophy: expansion of a trinucleotide (CTG) repeat at the 3' end of a transcript encoding a protein kinase family member. Cell. 1992 Feb 21;68(4):799–808. doi: 10.1016/0092-8674(92)90154-5. [DOI] [PubMed] [Google Scholar]
- Brunner H. G., Smeets H. J., Nillesen W., van Oost B. A., van den Biezenbos J. B., Joosten E. M., Pinckers A. J., Hamel B. C., Theeuwes A. G., Wieringa B. Myotonic dystrophy. Predictive value of normal results on clinical examination. Brain. 1991 Oct;114(Pt 5):2303–2311. doi: 10.1093/brain/114.5.2303. [DOI] [PubMed] [Google Scholar]
- Buxton J., Shelbourne P., Davies J., Jones C., Van Tongeren T., Aslanidis C., de Jong P., Jansen G., Anvret M., Riley B. Detection of an unstable fragment of DNA specific to individuals with myotonic dystrophy. Nature. 1992 Feb 6;355(6360):547–548. doi: 10.1038/355547a0. [DOI] [PubMed] [Google Scholar]
- Dyken P. R., Harper P. S. Congenital dystrophia myotonica. Neurology. 1973 May;23(5):465–473. doi: 10.1212/wnl.23.5.465. [DOI] [PubMed] [Google Scholar]
- Harley H. G., Brook J. D., Rundle S. A., Crow S., Reardon W., Buckler A. J., Harper P. S., Housman D. E., Shaw D. J. Expansion of an unstable DNA region and phenotypic variation in myotonic dystrophy. Nature. 1992 Feb 6;355(6360):545–546. doi: 10.1038/355545a0. [DOI] [PubMed] [Google Scholar]
- Norman A. M., Floyd J. L., Meredith A. L., Harper P. S. Presymptomatic detection and prenatal diagnosis for myotonic dystrophy by means of linked DNA markers. J Med Genet. 1989 Dec;26(12):750–754. doi: 10.1136/jmg.26.12.750. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reardon W., Floyd J. L., Myring J., Lazarou L. P., Meredith A. L., Harper P. S. Five years experience of predictive testing for myotonic dystrophy using linked DNA markers. Am J Med Genet. 1992 Aug 1;43(6):1006–1011. doi: 10.1002/ajmg.1320430618. [DOI] [PubMed] [Google Scholar]
- Systemic treatment of early breast cancer by hormonal, cytotoxic, or immune therapy. 133 randomised trials involving 31,000 recurrences and 24,000 deaths among 75,000 women. Early Breast Cancer Trialists' Collaborative Group. Lancet. 1992 Jan 4;339(8784):1–15. [PubMed] [Google Scholar]