The c.557C>T variant in ITGB3 is a missense variant predicted to cause substitution of proline by leucine at amino acid 186. The variant has a high population minor allele frequency in gnomAD v2.1.1 of 0.007131 (178/24960) in the African/African American population, which is higher than the ClinGen PD VCEP threshold (>0.0024). The computational predictor REVEL gives a score of 0.733, which is above the ClinGen PD VCEP PP3 threshold of >0.7 and predicts a damaging effect on ITGB3 function. It is reported to have an association with lower platelet count in an African American cohorts (PMID: 23103231) but has not been reported in a Glanzmann thrombasthenia patient to our knowledge. In summary, this variant meets the criteria to be classified as a variant of unknown significance - conflicting evidence for autosomal recessive Glanzmann Thrombasthenia based on the ACMG/AMP criteria applied, as specified by the ClinGen PD VCEP: BA1, PP3. (VCEP specifications version 2; date of approval 2/2/2023)