The c.70T>C (p.Cys24Arg) variant in GP9 is a missense variant predicted to cause substitution of cystine by arginine at amino acid 24. This variant has been detected in at least 14 probands with Bernard-Soulier syndrome. All 14 of these individuals were homozygous for this variant at least 2 of those were confirmed in trans by parental testing (PMIDs:23402648, 21699652, 21173099, 11167791, 29119711; PM3). At least one patient (Patient BSS2.01 in PMID:23402648) with this variant had aggregation absent for ristocetin and present for all other agonists, which is highly specific for Bernard-Soulier syndrome (PP4). Additionally, the patient had macrothrombocytopenia which is consistent with Bernard-Soulier syndrome. The variant has been reported to segregate with Bernard-Soulier syndrome in the proband (meeting PP4) plus one affected family member, both with the homozygous genotype with the p.Cys24Arg variant. (PP1; PMID:21173099). The computational predictor REVEL gives a score of 0.732, which is above the ClinGen PD VCEP threshold of >0.644 and predicts a damaging effect on function (PP3). The human copy of this variant failed to rescue thrombocytopenia when expressed in mutant thrombocytopenic zebrafish embryos. 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: PM3, PP1, PP3, PP4, PS3_supporting. (VCEP specifications version 1)