CNBP Repeat Expansion Testing
Description
Pathogenic CCTG repeat expansions in the CNBP gene have been associated with autosomal dominant myotonic dystrophy type 2 (DM2). The pathogenic repeat expansions lead to RNA toxicity.
Pathogenicity is dependent upon CCTG repeat length according to the following ranges 1-4:
Normal Alleles | Mutable Normal Alleles | Intermediate or Uncertain Alleles | Reduced Penetrance Alleles | Full Penetrance Alleles |
29 or fewer | 30-54 | 55-74 | - | 75 or more |
Note: As DM2 is typically adult onset, CNBP repeat expansions are not reported in minors in comprehensive analyses.