PRNP Repeat Expansion Testing
Description
Pathogenic expansions within an octapeptide region of the PRNP gene have been associated with autosomal dominant prion diseases including Creutzfeldt–Jakob disease, Gerstmann-Sträussler-Scheinker syndrome, and Huntington’s disease-like.
Pathogenicity is dependent upon octapeptide repeat length according to the following ranges 1-4:
Normal Alleles | Mutable Normal Alleles | Intermediate or Uncertain Alleles | Reduced Penetrance Alleles | Full Penetrance Alleles |
24*4=96 | - | - | - | 5-16 or deletion of 2 |
Note: As prion diseases are typically adult onset, PRNP repeat expansions are not reported in minors in comprehensive analyses.