NM_000267.3:c.4270-9A>T is an intronic substitution located at position -9 of the intron 32 splice acceptor site in NF1.¹ The variant is absent from gnomAD v2.1 and present at extremely low frequency in gnomAD v4.1 (7/1,541,860 alleles, AF = 0.00045%, no homozygotes), satisfying PM2_supporting.² SpliceAI predicts no splicing impact (max delta score = 0.00), supporting BP4_supporting.³ A reputable clinical laboratory (Labcorp Genetics/Invitae) has classified this variant as Likely benign in ClinVar (Variation ID: 849602), satisfying BP6_supporting.⁴ No pathogenic criteria were met. PVS1 is not applicable as the variant is outside canonical splice sites and SpliceAI predicts no impact. No de novo (PS2/PM6), functional (PS3/BS3), segregation (PP1/BS4), or case-control (PS4) evidence was identified for this variant.⁵ With three supporting benign criteria (PM2_supporting, BP4_supporting, BP6_supporting) and no pathogenic criteria met, the variant is classified as Likely Benign per generic ACMG/AMP 2015 combination rules.⁶