NM_000268.3:c.604G>T (p.Glu202Ter) is a nonsense variant in exon 7 of NF2, creating a premature termination codon predicted to trigger nonsense-mediated decay or produce a severely truncated merlin protein lacking the FERM domain F3 lobe and all downstream domains.¹ NF2 is a well-established tumor suppressor gene where germline loss-of-function variants cause NF2-related schwannomatosis, an autosomal dominant tumor predisposition syndrome characterized by bilateral vestibular schwannomas, meningiomas, and other nervous system tumors.² Truncating NF2 mutations, including nonsense variants, are associated with a more severe disease phenotype with earlier age of onset compared to missense or splice site mutations, as demonstrated in the largest genotype-phenotype study of 125 NF2 families.³ The variant is absent from gnomAD v2.1 (~141,456 individuals) and gnomAD v4.1 (~807,162 individuals), consistent with a rare disease-causing variant not tolerated in the general population.⁴ The premature stop at codon 202 occurs within the FERM domain, a critical functional domain required for merlin membrane association and tumor suppressor activity; the truncation removes the F3 subdomain and all C-terminal domains essential for merlin-mediated growth regulation.⁵ Combined evidence satisfies ACMG/AMP Pathogenic classification: PVS1 (Very Strong) + PM2 (Moderate) + PM1 (Moderate).⁶