Proximal Myotonic Myopathy (PROMM; DM2)

Overview

● DM2: Epidemiology Most families European, especially German/Polish Anticipation 6 Mild: 0.5 to 1.9 decades (vs 2.9 decades in myotonic dystrophy) ? More prominent with paternal transmission Genetics: Mutation in CCTG repeat sequence in intron 1 of ZNF9 gene 12 Normal CCTG repeat sequence Complex repeat motif: (TG)n(TCTG)n(CCTG)n Size: 104 to 176 base pairs Interruptions: GCTG + TCTG motifs, or one or two TCTG motifs CCTG expansion (CCTG)n repeat size: Range 75 to ~11,000; Mean ~5000 Interruptions: None No clear relation of CCTG repeat size with: Onset age; Disease severity Somatic instabilit

OMIM Entries

External Resources