The InSiGHT MMR VCEP BS1_Strong criterion is met: gnomAD v4.1 grpmax filtering allele frequency of 0.033% (0.00033148) falls within the 0.01-0.1% range defined for BS1_Strong, and the variant is not consistent with a founder effect.¹ PM2_Supporting is not met: the gnomAD v4.1 allele frequency of 0.0036% exceeds the VCEP threshold of < 0.002% (< 1 in 50,000 alleles).² PP3 is not met: the HCI prior probability of 0.3778 is below the PP3_Supporting threshold of > 0.68, and SpliceAI predicts no splicing impact (delta = 0.00).³ PVS1 is not applicable: this is a missense variant (p.Ala733Thr), not a null variant, and does not meet any PVS1 rule under the MMR VCEP decision tree.⁴ PS3 remains not assessed: the VCEP-calibrated functional assay (PMID:33357406) likely includes this variant but variant-specific confirmation was not available in this review.⁵ Under the InSiGHT MMR VCEP v2.0.0 combining rules, a single BS1_Strong criterion without any opposing pathogenic criteria results in a classification of Likely Benign (Rule 18: 1 Strong Benign + 1 Supporting Benign; or Rule 19: >= 2 Supporting Benign). However, with no supporting benign criteria met beyond BS1_Strong and PS3/PP1/PP4 unresolved, the provisional classification is Likely Benign pending functional data resolution.⁶