Supplementary Table S1 & S2 Proband and Variant Information:

Case59: GT61, Female, 49 years old, French/Italian

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: HP:0000978, HP:0000132

(Easy bruising, menorrhagia)

CaseHPOFreeText: Tonsil bleeding

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: ITGB3

Variant: NM_000212.2:c.224del

LegacyVariant: N/A

ClinVar: N/A

CAiD: CA8622899

gnomAD: MAF in the European (non-Finnish) population is 0.000008795 https://gnomad.broadinstitute.org/variant/17-45360777-TG-T

Supplementary Table S1:

Case52: GT61, French/Italian, gender and age are 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: ITGB3

Variant: NM_000212.2:c.224del (p.Cys75LeufsTer10)

LegacyVariant: N/A

ClinVar: N/A

CAiD: CA8622899

gnomAD: N/A

Case3: Patient MR, gender and age are not specified, all of these patients are Caucasian (either Italian or European)

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: All patients presented with a current or past history of bleeding and a bleeding time >15 min. Bleeding symptoms were evaluated by examining available hospital records. Mild bleeders were defined as those who bled only after trauma or surgery or had minor symptoms, such as epistaxis. Moderate/severe bleeders were defined as those with a history of spontaneous or life threatening hemorrhages, such as gastrointestinal bleeding, or who had repeated episodes requiring platelet transfusions

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: See Table 1

PlateletAggregation: See Table 1

CasePreviousTesting: To identify point mutations responsible for GT, we have sequenced all coding regions of Ib and 3 genes and intron/exon boundaries.

Gene: ITGA2B and ITGB3

Variant: NM_000419.3:c.526C>G (p.Pro176Ala) and NM_000212.2:c.224del ,

LegacyVariant: (p.Pro145Ala)

ClinVar: N/A

CAiD: CA399805793 and CA8622899

gnomAD: MAF in the European non Fin pop is 0.000008795 for the ITGB3 variant