NM_000314.8:c.431A>C (NP_000305.3:p.Lys144Thr) is a missense variant in exon 5 of PTEN. This variant is absent from gnomAD v2.1 and v4.1 (PM2_Supporting per VCEP).¹ PTEN has a low rate of benign missense variation and missense variants are a common disease mechanism (PP2_Supporting per VCEP).² Functional data from Mighell et al. 2018 saturation mutagenesis assay shows a cumulative fitness score of -0.15 for K144T, indicating mild functional impairment that does not meet PS3 or BS3 thresholds.³ REVEL score of 0.691 does not exceed the VCEP PP3 threshold of >0.7; SpliceAI predicts no splice impact.⁴ The variant lies outside the PTEN catalytic motifs (residues 90-94, 123-130, 166-168); PM1 is not met.⁵ This variant has been reported in ClinVar as Uncertain Significance (1 submitter, VCV2687516). It has been observed somatically in 3 cancer samples (COSMIC COSV64295211).⁶ No case-level proband data, de novo observations, co-segregation data, or same-residue pathogenic comparator variants were identified. With 2 supporting-level pathogenic criteria (PM2_Supporting, PP2_Supporting) and no benign criteria met, the variant does not reach the combination threshold for Likely Pathogenic or Pathogenic under the PTEN VCEP v3.2.0 rules. The variant remains a Variant of Uncertain Significance.⁷