Systematic analysis of short tandem repeats in 38,095 exomes provides an additional diagnostic yield

Bart P G H van der Sanden, Jordi Corominas, Michelle de Groot, Maartje Pennings, Rowdy P P Meijer, Nienke Verbeek, Bart van de Warrenburg, Meyke Schouten, Helger G Yntema, Lisenka E L M Vissers, Erik-Jan Kamsteeg, Christian Gilissen

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

PURPOSE: Expansions of a subset of short tandem repeats (STRs) have been implicated in approximately 30 different human genetic disorders. Despite extensive application of exome sequencing (ES) in routine diagnostic genetic testing, STRs are not routinely identified from these data.

METHODS: We assessed diagnostic utility of STR analysis in exome sequencing by applying ExpansionHunter to 2,867 exomes from movement disorder patients and 35,228 other clinical exomes.

RESULTS: We identified 38 movement disorder patients with a possible aberrant STR length. Validation by polymerase chain reaction (PCR) and/or repeat-primed PCR technologies confirmed the presence of aberrant expansion alleles for 13 (34%). For seven of these patients the genotype was compatible with the phenotypic description, resulting in a molecular diagnosis. We subsequently tested the remainder of our diagnostic ES cohort, including over 30 clinically and genetically heterogeneous disorders. Optimized manual curation yielded 167 samples with a likely aberrant STR length. Validations confirmed 93/167 (56%) aberrant expansion alleles, of which 48 were in the pathogenic range and 45 in the premutation range.

CONCLUSION: Our work provides guidance for the implementation of STR analysis in clinical ES. Our results show that systematic STR evaluation may increase diagnostic ES yield by 0.2%, and recommend making STR evaluation a routine part of ES interpretation in genetic testing laboratories.

Original languageEnglish
Pages (from-to)1569-1573
Number of pages5
JournalGenetics in medicine : official journal of the American College of Medical Genetics
Volume23
Issue number8
Early online date12 Apr 2021
DOIs
Publication statusPublished - Aug 2021

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