Krndija, D. (23060728300)D. (23060728300)KrndijaSavić, D. (18435454500)D. (18435454500)SavićMladenović, J. (8310875700)J. (8310875700)MladenovićRakocevc-Stojanovic, V. (8310875800)V. (8310875800)Rakocevc-StojanovicApostolski, S. (7004532054)S. (7004532054)ApostolskiTodorović, S. (7005263658)S. (7005263658)TodorovićRomac, Stanka (7003983993)Stanka (7003983993)Romac2025-06-132025-06-132005https://doi.org/10.1111/j.1600-0404.2005.00402.xhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-15244341061&doi=10.1111%2fj.1600-0404.2005.00402.x&partnerID=40&md5=3b2fb198243e9210a4765cc01c7b4688https://remedy.med.bg.ac.rs/handle/123456789/11123Objectives - Analysis of the CTG-repeat number and three biallelic markers, Alu(+/-), HinfI(+/-), and TaqI(+/-), in the DMPK gene in healthy and myotonic dystrophy type 1 (DM1) Serbian individuals. Also, the consideration of haplotypes in the light of the proposed models of CTG-repeat evolution and origin of the DM1 mutation. Materials and methods - Markers were analyzed by PCR and haplotypes were obtained on 203 unrelated normal chromosomes and 24 unrelated DM1 chromosomes. Results - A strong linkage disequilibrium was detected between the three biallelic markers alone (P < 0.0001) and between distinct CTG-repeat size classes and reconstructed haplotypes. Greater than 98% of normal chromosomes contain (+ + +) and (- - -) haplotypes. The (+ + +) haplotype is the most common, while the (CTG) 9-17 are the most frequent alleles. We found a complete association of (+ + +) haplotype with (CTG) ≥18 and mutated alleles. Conclusions - (CTG) 9-17 /(+ + +) haplotype is the ancestral haplotype and DM1 mutation occurred on (CTG) 18-35 / + + + chromosome. Copyright © Blackwell Munksgaard 2005.CTG repeatsDM1Haplotype analysesLinkage disequilibriumMyotonic dystrophy type 1