Why I . . . am a Brownie leader

Background: The myotonic dystrophies (DM1, DM2) are the most common adult muscle diseases and characterized by multisystem involvement. DM1 has been described in diverse populations, whereas DM2 seems to occur primarily European Caucasians. Both caused expression of expanded microsatellite repeats. In DM1, there is a reservoir premutation alleles; however, have no reported alleles for DM2. (CCTG)DM2 expansion part complex polymorphic repeat tract form (TG)n(TCTG)n(CCTG)n(NCTG)n(CCTG)n. Expansions as large 40 kb, with (CCTG)n motif uninterrupted. Reported normal up (CCTG)26 one or more interruptions. Methods: To identify characterize potential alleles, we cloned sequenced 43 from 23 individuals. Uninterrupted were identified, their instability was confirmed small-pool PCR. We determined genotype nearby single nucleotide polymorphism (rs1871922) known be linkage disequilibrium mutation. Results: identified three classes non-DM2 alleles: 1) (CCTG)24 two interruptions, 2) (CCTG)32 four 3) uninterrupted (CCTG)22–33. Large African Americans than significantly unstable interrupted (p = 10−4 10−7). Genotypes at rs1871922 consistent hypothesis that all on same haplotype expansion. Conclusions: conclude (CCTG)22-33 represent allele pool full mutations.