DIP2B Repeat Expansion Testing
Description
Pathogenic CGG repeat expansions within the 5′ untranslated region of the DIP2B gene have been associated with autosomal dominant FRA12A type intellectual developmental disorder. The pathogenic repeat expansions may lead to promoter hypermethylation.
Pathogenicity is dependent upon CGG repeat length according to the following ranges 1-2:
Normal Alleles | Mutable Normal Alleles | Intermediate or Uncertain Alleles | Reduced Penetrance Alleles | Full Penetrance Alleles |
6-37 | - | 150-269 | - | 270 or more |
Additional Resources
Missed by Others, Found by Us
A 10-year-old female presented with chronic symptoms including developmental delay and seizures controlled by medicine. Prior exome testing was negative. Variantyx testing identified a pathogenic DIP2B expansion of >500 repeats.