Repeat Expansion Detection with ExpansionHunter
Short tandem repeats (STRs) are regions of the genome consisting of repetitions of short DNA segments called repeat units. STRs can expand to lengths beyond the normal range and cause mutations called repeat expansions. Repeat expansions are responsible for many diseases, including Fragile X syndrome, amyotrophic lateral sclerosis, and Huntington's disease.
DRAGEN includes a repeat expansion detection method called ExpansionHunter. ExpansionHunter performs sequence-graph based realignment of reads that originate inside and around each target repeat. ExpansionHunter then genotypes the length of the repeat in each allele based on these graph alignments.
More information and analysis are available in the following ExpansionHunter papers:
| • | Dolzhenko et al., Detection of long repeat expansions from PCR-free whole-genome sequence data 2017 |
| • | Dolzhenko et al., ExpansionHunter: A sequence-graph based tool to analyze variation in short tandem repeat regions 2019 |
