The missense variant NM_000407.5(GP1BB):c.397G>C (p.Ala133Pro) has a Grpmax Filtering allele frequency in gnomAD v4.1 is 0.00002722 (based on 3/29196 alleles) in the East Asian population, which is lower than the ClinGen PD VCEP threshold (<0.00006517; PM2_Supporting). At least one patient (Patient A.K. in PMID: 9116284) with this variant had aggregation absent for ristocetin and present for all other agonists and flow cytometry found the expression of GPIbα, the GPIb/IX complex, and GPIX were remarkably lower than the normal control. which is highly specific for Bernard-Soulier syndrome (PP4). Additionally, the patient had excessive mucocutaneous bleeding and macrothrombocytopenia which are consistent with Bernard-Soulier syndrome. The patient is compound heterozygote has been reported with Tyr113Cys (provisionally classified Likely Pathogenic by PD VCEP) and Ala133Pro confirmed in trans from heterozygous parents (PMID: 9116284; PM3). There is segregation of this variant in 1 additional compound heterozygous BSS family member (PMID: 9116284; total 1pt, PP1). In transiently transfected CHO cells HA-GPIbβ was present on the cell surface but GPIX was not (PMID: 21908432). In transiently transfected CHO cells HA-GPIbβ was present on the cell surface around 20% but GPIX was absent (PMID: 21908432; PS3_supporting). In summary, this variant meets the criteria to be classified as Likely Pathogenic for autosomal recessive Bernard-Soulier syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen PD VCEP: PS3_supporting, PM3, PM2_supporting, PP1, PP4.