Supplementary Table S1:

Case38: GT44, French, age and gender not specified

DiseaseAssertion: Glanzmann thrombasthenia type I

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: All patients had a life-long history of mucocutaneous bleeding

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: All patients in this study met the clinical and platelet function requirements for GT-- this includes an absent or strongly reduced expression of alphaIIbBeta3 in platelets

PlateletAggregation: All patients in this study met the clinical and platelet function requirements for GT-- this includes absent or severely reduced platelet aggregation with at least three physiological agonists

CasePreviousTesting: Sanger sequencing was performed. Sanger sequencing ensured coverage of all exons and splice sties of the ITGA2B and ITGB3 genes and extended 300-500 bp into the introns as well as including the UTR. They sequenced 416 bp upstream of the ITGA2B promoter and 463 bp upstream of the ITGB3 promoter. In total they sequenced 51.2% of the ITGA2B gene and 19.4% of the larger ITGB3 gene

Gene: ITGA2B

Variant: NM_000419.3:c.1357C>T (p.Arg453Ter)

LegacyVariant: N/A

ClinVar: 631773

CAiD: CA399803529

gnomAD: N/A

Supplementary Table S1 & S2 Proband and Variant Information:

Case45: GT44, Female, 10 years old, French

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Flow cytometry showed <5% 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.1357C>T (p.Arg453Ter)

LegacyVariant: N/A

ClinVar: 631773

CAiD: CA399803529

gnomAD: N/A

Case1: Female, 9 years old, Japanese

DiseaseAssertion: Macrothrombocytopenia

FamilyInfo: Information given in Table 1 and Fig 2

ParentalGenotype: Mother: ITGA2B (p.Arg422Ter heterozygous) and Father: ITGA2B (p.Gly991Cys heterozygous) See Table 1 for this information

Sequencing of parental DNA indicated parental mutations. CasePresentingHPOs: HP:0000979, HP:0000421, HP:0000978

(Purpura, epistaxis, bruising)

CaseHPOFreeText: Hemorrhage after dental

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Flow cytometric analysis showed that surface αIIbβ3 expression in platelets (was markedly impaired 3-11%)

PlateletAggregation: N/A

CasePreviousTesting: Sequence analysis of entire coding regions of exons and exon-intron boundaries of ITGA2B and ITGB3 gene of the patient revealed two novel mutations in ITGA2B.

Gene: ITGA2B

Variant: NM_000419.3:c.3064G>T (p.Gly1022Cys) and NM_000419.3:c.1357C>T (p.Arg453Ter)

LegacyVariant: (p.Gly991Cys legacy nomenclature for p.Gly1022Cys) and (p.Arg422Ter legacy nomenclature for p.Arg453Ter)

ClinVar: 631773

CAiD: CA399787943 and CA399803529

gnomAD: N/A

Case13: Female, African, age not specified

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: N/A

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: ITGA2B

Variant: NM_000419.3:c.1357C>T (p.Arg453Ter)

LegacyVariant: N/A

ClinVar: 631773

CAiD: CA399803529

gnomAD: N/A