The NM_001482.3:c.845G>A variant in GATM is a missense variant that is predicted to result in the substitution of arginine by histidine at amino acid 282 (p.Arg282His). To our knowledge, this variant has not been reported in an individual with AGAT deficiency in the published literature. The highest population minor allele frequency for this variant in gnomAD v2.1.1 is 0.00003 (1/34578 alleles) in the Latino population, which is lower than the ClinGen CCDS VCEP’s threshold for PM2_Supporting (<0.000055), meeting this criterion (PM2_Supporting). When overexpressed in HeLa cells, the variant resulted in <15% of wild-type GATM enzyme activity (PMID: 27233232) (PS3_Supporting). The computational predictor REVEL gives a score of 0.382 which is neither above nor below the thresholds predicting a damaging (>0.75) or benign (<0.15) impact on AGAT function. There is a ClinVar entry for this variant (Variation ID: 225918). In summary, this variant meets the criteria to be classified as a variant of uncertain significance for AGAT deficiency. GATM-specific ACMG/AMP criteria applied, as specified by the ClinGen CCDS VCEP (Specifications Version 1.1.0): PS3_Supporting; PM2_Supporting. (Classification approved by the ClinGen CCDS VCEP on January 24, 2023).