NM_000051.4:c.7974T>C is a synonymous variant p.(Asn2658=) in ATM exon 54, located well outside the canonical splice consensus regions. SpliceAI predicts no splice impact (max delta score = 0.00).¹ This variant is present in gnomAD v4.1 at very low frequency (total AF = 0.00031%, 5/1,611,834 alleles, 0 homozygotes), highest in East Asian population (sub-population AF = 0.011%).² ClinVar reports this variant as Likely benign (4 clinical laboratories) and Benign (1 laboratory); review status: criteria provided, single submitter (ClinVar Variation ID: 414583).³ The ClinGen HBOP VCEP supplementary table (PMID:40580951, Table S1) classifies this variant as Likely benign with an eDA score of 3.10e-06.⁴ BP7_Supporting is met: synonymous variant outside donor +7 and acceptor -21 splice regions with no predicted splice impact (SpliceAI = 0.0).⁵ BP4_Supporting is met: no predicted impact via splicing (SpliceAI max delta = 0.0 ≤ 0.1). Note partial overlap with BP7.⁶ PM2_Supporting is met: gnomAD v4.1 total allele frequency (0.00031%) is ≤ 0.001% VCEP threshold. Per VCEP guidance, PM2 is not considered conflicting evidence for variants that otherwise are likely benign/benign.⁷ No pathogenic criteria beyond PM2_Supporting are met. Multiple benign supporting criteria (BP7, BP4) are met with no conflicting pathogenic evidence per VCEP PM2 guidance.⁸ The ClinGen HBOP Expert Panel classification from the VCEP supplementary table is Likely benign, which is concordant with the evidence-based assessment.⁹