TANDEM REPEAT EXPANSIONS
with Genomic Unity®
Tandem repeat expansions tested
More than 20 known pathogenic loci are covered by Genomic Unity® testing
A significant number of inherited disorders are caused by the pathogenic expansion of tandem repeats – short sequences of DNA, typically 1 to 6 nucleotides in length, that repeat consecutively. Most repeats within the genome do not have a discernible function, but some have the potential to become pathogenic when the number of repeats exceeds a particular threshold.
Our WGS-based Genomic Unity® testing methodology detects repeat expansions in the following important genes.
|Gene||Repeat||Disorder||Tests included in|
|AFF2||CCG||Fragile XE syndrome|
|AFF3||CGG||FRA2A fragile site|
|AR||CAG||Spinal and bulbar muscular dystrophy|
|ATN1||CAG||Dentatorubral-pallidoluysian atrophy (DRPLA)|
|ATXN1||CAG||Spinocerebellar ataxia 1 (SCA1)|
|ATXN2||CAG||Spinocerebellar ataxia 2 (SCA2)|
|ATXN3||CAG||Spinocerebellar ataxia 3 (SCA3)|
|ATXN7||CAG||Spinocerebellar ataxia 7 (SCA7)|
|ATXN8OS||CTG||Spinocerebellar ataxia 8 (SCA8)|
|ATXN10||ATTCT||Spinocerebellar ataxia 10 (SCA10)|
|C9ORF72||GGGGCC||Frontotemporal dementia and/or amyotrophic lateral sclerosis (FTDALS1)|
|CACNA1A||CAG||Spinocerebellar ataxia 6 (SCA6)|
|CNBP||CCTG||Myotonic dystrophy type II|
|DIP2B||CGG||Fragile X syndrome|
|DMPK||CTG||Myotonic dystrophy type I|
|FMR1||CGG||Fragile X syndrome|
|JPH3*||CTG||Huntington disease-like 2|
|NOP56||Spinocerebellar ataxia 36 (SCA36)|
|NOTCH2NLC||GGC||Neuronal intranuclear inclusion disease|
|PHOX2B||Alanine||Congenital central hypoventilation syndrome|
|PPP2R2B||CAG||Spinocerebellar ataxia 12 (SCA12)|
|TBP||Glutamine||Spinocerebellar ataxia 17 (SCA17)|
|TCF4||CAG||Fuchs endothelial corneal dystrophy|
*HTT and JPH3 testing requires special consent.
Sensitivity and reporting policies differ by loci. The false negative rate for repeat expansions has not been determined for the following genes: AFF2, AFF3, ATXN10, CNBP, CSTB, DIP2B, JPH3, NOTCH2NLC, PHOX2B, TBP, TCF4.
The following genes can be assessed for normal repeat ranges only: AFF3, DIP2B, JPH3, NOTCH2NLC, TCF4. Repeat counts falling outside the normal range will be reported as indeterminate.
To learn more about how we detect and analyze tandem repeat expansions, read our blog post: Detecting short tandem repeats using WGS.