Blog

January 9, 2019

Expanded coverage of repeat expansion loci

With a growing number of different pathogenic repeat expansions linked to human disease, genetic testing for this unique class of mutations is an important component of the diagnostic process for many patients. Particularly those experiencing symptoms associated with developmental delay, neuromuscular and neurodegenerative disorders.

In previous posts, we’ve talked about the role of repeat expansions in fragile X syndrome and inherited ataxias. We’ve also detailed the strategy that our proprietary algorithms use to detect these and other repeat expansions as part of our Genomic Unity® testing methodology. A test which is uniquely based on clinical whole genome sequencing (WGS).

Today we’re excited to share that we’ve expanded the number of pathogenic repeat expansion loci covered in this single genetic test to a total of 21!

Pathogenic repeat expansion loci screened by Genomic Unity®

LociRepeatDisorder
AFF2CCGFragile XE syndrome
ARCAGSpinal and bulbar muscular atrophy
ATN1CAGDentatorubral-pallidoluysian atrophy (DRPLA)
ATXN1CAGSpinocerebellar ataxia 1 (SCA1)
ATXN10ATTCTSpinocerebellar ataxia 10 (SCA10)
ATXN2CAGSpinocerebellar ataxia 2 (SCA2)
ATXN3CAGSpinocerebellar ataxia 3 (SCA3)
ATXN7CAGSpinocerebellar ataxia 7 (SCA7)
ATXN8OSCTGSpinocerebellar ataxia 8 (SCA8)
C9ORF72GGGGCFrontotemporal dementia and/or amyotrophic lateral sclerosis (FTDALS1)
CACNA1ACAGSpinocerebellar ataxia 6 (SCA6)
CNBPCCTGMyotonic dystrophy type II
CSTBCCCCGCCCCGCGMyoclonus epilepsy
DIP2BCGGFRA12A fragile site
DMPKCTGMyotonic dystrophy type I
FMR1CGGFragile X syndrome
FXNGAAFriedreich’s ataxia
HTTCAGHuntington disease
JPH3CTGHuntington disease-like 2 syndrome
PPP2R2BCAGSpinocerebellar ataxia 12 (SCA12)
Note: The data above is current as of January 10, 2019. The most up-to-date list can be found in the STRs tested page of the Resources section.

The expansion is the result of ongoing refinement and calibration of our algorithms.