Supplementary Table S1 & S2 Proband and Variant Information:

Case12: GT13, Female, 14, French

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: HP:0000967 (Petechiae)

CaseHPOFreeText: Moderate bleeding syndrome

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Flow cytometry showed <5% variant expression of αIIbβ3 (See Supplementary Table 1)

PlateletAggregation: Absent platelet aggregation (See Supplementary Table 1)

CasePreviousTesting: Sanger sequencing of ITGA2B and ITGB3

Gene: ITGA2B

Variant: NM_000419.3:c.682C>T (p.Gln228Ter) and NM_000419.3:c.1750C>T (p.Arg584Ter)

LegacyVariant: N/A

ClinVar: 2892

CAiD: CA399805421 and CA115834

gnomAD: MAF in the East Asian population is 0.0002176 http://gnomad.broadinstitute.org/variant/17-42457372-G-A

Case8: Female, age not specified

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: Mild bleeding

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: N/A

PlateletAggregation: Minimal information, not specific enough

CasePreviousTesting: Sanger sequencing identified disease-causing variants in 18 out of 20 patients (Probands 6 and 14 excluded) with istoantibodies to αIIbβ3. The mutations were evenly distributed between ITGB3 and ITGA2B.

Gene: ITGB3 and ITGA2B

Variant: NM_000419.3:c.682C>T (p.Gln228Ter) and NM_000419.3:c.1750C>T (p.Arg584Ter)

LegacyVariant: N/A

ClinVar: 2892 (p.Arg584Ter)

CAiD: CA115834 (p.Arg584Ter) and CA399805421

gnomAD: MAF in East Asian population 0.0002176 (p.Arg584Ter) http://gnomad.broadinstitute.org/variant/17-42457372-G-A

Case8: (GT-8) Female, 10 years old, French

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: Mucocutaneous bleeding

CaseNotHPOs: N/A

ProteinExpression: <5% surface expression levels of αIIbβ3

Platelet Aggregation: Absent platelet aggregation to all agonists (no mention for which agonists or response to ristocetin)

CasePreviousTesting: All the information we are given is "mutation screening of the ITGA2B and ITGB3 genes" the method for sequencing etc. was not stated

Gene: ITGA2B

Variant: NM_000419.3:c.682C>T (p.Gln228Ter) and NM_000419.3:c.1750C>T (p.Arg584Ter)

LegacyVariant: (p.Gln197Ter) and (p.Arg558Ter) (The paper gives legacy and current nomenclature)

ClinVar: 2892 (p.Arg584Ter)

CAiD: CA399805421 (p.Gln228Ter) CA115834 (p.Arg584Ter)

gnomAD MAF in the East Asian population is 0.0002176 https://gnomad.broadinstitute.org/variant/17-42457372-G-A