The ATM c.4300A>T (p.Lys1434Ter; p.K1434*) variant has not been observed in somatic cancers in COSMIC and has not been reported in ClinVar.¹ This variant is absent from gnomAD v2.1 and gnomAD v4.1, placing it below the ATM VCEP PM2_Supporting threshold of 0.001% and well below the BS1 (>0.05%) and BA1 (>0.5%) thresholds.² This is a nonsense variant predicted to introduce a premature stop codon at Lys1434; SpliceAI predicts no significant splice impact with a maximum delta score of 0.03, supporting interpretation as a truncating loss-of-function event rather than a splice-altering event.³