P186: STRtr-Kit: A classification system and evidence criteria for tandem repeat-disease relationships

Tandem repeats (TRs)—including short tandem repeats (1-6 bp motifs) and variable number tandem repeats (7+ bp motifs)—have been linked to dozens of Mendelian diseases, such as Huntington’s, and several forms of ataxia and epilepsy. Current frameworks for evaluating gene-disease relationships do not adequately address TR-specific complexities. For example, TR diseases often show genetic anticipation, where the age of onset and severity are associated with increasing allele size. As a result, proposed TR-disease relationships are often incorrectly classified, under-evaluated, or excluded entirely, limiting discovery and hindering clinical application.