RUNX2 Repeat Expansion Testing

Description

The RUNX2 gene contains an N-terminal stretch of 23 uninterrupted glutamine residues (polyQ) followed by 17 uninterrupted alanine residues (polyA), with a single glutamic acid spacing between them (E), known as the Q/A domain. Pathogenic alanine repeat expansions within the RUNX2 gene have been associated with autosomal dominant cleidocranial dysplasia. Expansions in the polyA tract or the polyQ tract cause loss of transactivation potential of the RUNX2 protein and/or form protein aggregates.

Pathogenicity is dependent upon GCN repeat length according to the following ranges 1-3:

Normal Alleles

Mutable Normal Alleles

Intermediate or Uncertain Alleles

Reduced Penetrance Alleles

Full Penetrance Alleles

18

-

19

-

20 or more

Tests That Analyze RUNX2 Repeats