{"title":"No increase in the CTG repeat size during transmission from parent with expanded allele: false suspicion of contraction phenomenon.","authors":"Nuria Goñi Ros, Paula Sienes Bailo, Ricardo González Tarancón, Loreto Martorell Sampol, Silvia Izquierdo Álvarez","doi":"10.1515/almed-2022-0079","DOIUrl":null,"url":null,"abstract":"<p><strong>Objectives: </strong>Myotonic dystrophy type 1 (DM1), also known as Steinert's disease, is a chronic, progressive and disabling multisystemic disorder with a broad spectrum of severity that arises from an autosomal-dominant expansion of the Cytosine-Thymine-Guanine (CTG) triplet repeat in the 3' untranslated region of the <i>DMPK</i> gene (19q13.3).</p><p><strong>Case presentation: </strong>In this study, we report the case of a family with several intergenerational expansions of the CTG repeat, with an additional case of a false suspicion of contraction phenomenon due to TP-PCR limitations.</p><p><strong>Conclusions: </strong>The meiotic instability of the (CTG)<sub>n</sub> repeats leads to genetic anticipation where increased size of DM1 mutation and a more severe phenotype have been reported in affected individuals across generations. Even if extremely rare, a decrease in the CTG repeat size during transmission from parents to child can also occur, most frequently during paternal transmissions.</p>","PeriodicalId":72097,"journal":{"name":"Advances in laboratory medicine","volume":"4 1","pages":"185-194"},"PeriodicalIF":1.1000,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10701496/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in laboratory medicine","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1515/almed-2022-0079","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2023/6/1 0:00:00","PubModel":"eCollection","JCR":"Q4","JCRName":"MEDICAL LABORATORY TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Objectives: Myotonic dystrophy type 1 (DM1), also known as Steinert's disease, is a chronic, progressive and disabling multisystemic disorder with a broad spectrum of severity that arises from an autosomal-dominant expansion of the Cytosine-Thymine-Guanine (CTG) triplet repeat in the 3' untranslated region of the DMPK gene (19q13.3).
Case presentation: In this study, we report the case of a family with several intergenerational expansions of the CTG repeat, with an additional case of a false suspicion of contraction phenomenon due to TP-PCR limitations.
Conclusions: The meiotic instability of the (CTG)n repeats leads to genetic anticipation where increased size of DM1 mutation and a more severe phenotype have been reported in affected individuals across generations. Even if extremely rare, a decrease in the CTG repeat size during transmission from parents to child can also occur, most frequently during paternal transmissions.