NM_000051.4:c.5488A>G (p.Met1830Val) is a missense variant in ATM, a gene in which loss of function is an established mechanism for ataxia telangiectasia (autosomal recessive) and where pathogenic variants confer moderate-risk susceptibility to hereditary breast, ovarian, and pancreatic cancer (autosomal dominant).¹ This variant is observed in gnomAD v4.1 at an overall allele frequency of 0.001675% (27/1,611,638 alleles; grpmax FAF = 0.0226%), which is rare but above the VCEP PM2 threshold of 0.001%, and does not meet BA1 (>0.5%), BS1 (>0.05%), or PM2_Supporting (≤0.001%) population thresholds.² VCEP-endorsed functional data (Table S1, PMID:40580951) classifies M1830V as 'Functional' with 'High' confidence (Combined_score = -0.63; DeepATM predicted not pathogenic), indicating the variant retains ATM function. This supports BS3_Supporting per VCEP rules.³ Computational predictors consistently suggest a benign impact: REVEL = 0.146 (BP4 threshold ≤0.249), BayesDel = -0.31326, AlphaMissense = 0.0733, and SpliceAI max delta = 0.04. This supports BP4_Supporting per VCEP rules.⁴ This variant has been reported in ClinVar as Uncertain significance by 7 clinical laboratories and Likely benign by 4 clinical laboratories (ClinVar Variation ID: 141271). It has been observed as a somatic variant (M1830V, VUS) in a metastatic pancreatic cancer case (PMID:27034805), but this somatic observation does not inform germline classification.⁵ Applying the VCEP HBOP ATM v1.5.0 framework: met criteria include BS3_Supporting and BP4_Supporting (2 benign supporting criteria). No pathogenic criteria are met. Per ACMG/AMP combination rules (Rule 19), ≥2 benign supporting criteria support a classification of Likely Benign.⁶