NM_000314.8:c.993C>A (p.Asp331Glu) in PTEN has a cumulative fitness score of -0.106 in the Mighell et al. 2018 saturation mutagenesis assay, indicating near-wild-type phosphatase activity that does not meet PS3 or BS3 thresholds.¹ The variant is absent from gnomAD v2.1, v4.1, and gnomAD-Canada, meeting VCEP PM2_Supporting (allele frequency <0.001%).² PP2_Supporting is applied as PTEN has a low rate of benign missense variation and missense variants are a well-established disease mechanism.³ The variant does not reside in VCEP-defined catalytic motifs (residues 90-94, 123-130, 166-168) and is not in a statistically significant hotspot, so PM1 is not met.⁴ REVEL score of 0.622 does not meet PP3 threshold (>0.7) or BP4 threshold (<0.5); computational evidence is indeterminate.⁵ No pathogenic or likely pathogenic comparator variant at codon 331 was identified in ClinVar; PM5 is not met.⁶ PVS1 is not applicable as this is a missense variant outside the scope of the PTEN PVS1 decision tree. PS2, PS4, PM6, PP1, BS4, BP2, and BP5 could not be assessed due to absence of clinical, de novo, segregation, or co-occurrence data.⁷ With two supporting pathogenic criteria (PM2_Supporting, PP2_Supporting) and no moderate, strong, or very-strong criteria met, the variant does not reach Likely Pathogenic under the PTEN VCEP combination rules. The variant is classified as a Variant of Uncertain Significance (VUS).⁸