NM_000249.4:c.381-1G>A is a canonical splice acceptor variant (IVS4-1) disrupting the invariant AG dinucleotide of MLH1 intron 4, meeting PVS1_Very_Strong under the InSiGHT/ClinGen MLH1 VCEP v2.0.¹ The variant is absent from gnomAD v2.1 and v4.1, meeting PM2_Supporting under the VCEP threshold of allele frequency <0.00002.² A patient with this variant, reported by Roth et al. (2016), had two synchronous colorectal cancers showing loss of MLH1 and PMS2 protein expression by immunohistochemistry, meeting PP4_Moderate under the VCEP rule for 2 independent tumors with MMR protein loss consistent with the variant location.³ This variant was identified as a recurrent mutation in 5 African American families with Lynch syndrome by Guindalini et al. (2015), supporting its enrichment in the Lynch syndrome patient population.⁴ ClinVar classifies this variant as Pathogenic (4 clinical laboratories) and Likely pathogenic (1 laboratory); however, the VCEP framework does not permit use of PP5 or BP6, and ClinVar classification alone is not used as an independent criterion.⁵ Combining PVS1_Very_Strong (1) + PP4_Moderate (1) under the InSiGHT/ClinGen MLH1 VCEP v2.0 combination rules (Rule 10) yields a classification of Likely Pathogenic.⁶