Supplementary Table S1 & S2 Proband and Variant Information:

Case6: GT7, Female, 19, French

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: 1 brother, that is all the information Supp table S1 gives us

ParentalGenotype: N/A

CasePresentingHPOs: HP:0000978 and HP:0000421

(Easy bruising and epistaxis)

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Flow cytometry showed <10-15% expression of αIIbβ3 (See Supplementary Table 1)

PlateletAggregation: Absent ADP but some response with other agonists (See Supplementary Table 1)

CasePreviousTesting: Sanger sequencing of ITGA2B and ITGB3

Gene: ITGB3

Variant: NM_000212.2:c.187C>T (p.Arg63Cys) and NM_000212.2:c.505C>T (p.Arg169Ter)

LegacyVariant: N/A

ClinVar: 631774

CAiD: CA8622892 and CA291224658

gnomAD: MAF in the East Asian population is 0.00005012 http://gnomad.broadinstitute.org/variant/17-45360741-C-T

Case#: Case 2, 20 yo Female

DiseaseAssertion: Glanzman thrombasthenia

ParentalGenotype: Not provided

CasePresentingHPOs: (HP:0000978, Bruising susceptibility) (HP:0000421, Epistaxis)

PlateletAggregation: Strong reduction of platelet aggregation with all agonists, except ristocetin. Normal platelet count.

CaseHPOFreeText:

CaseNotHPOs:

CaseNotHPOFreeText:

ProteinExpression: Flow cytometry, platelets with 18% to 24% residual αIIbβ3

CasePreviousTesting: Not provided

PreviouslyPublished: Not provided

Gene: ITGB3

HGVS: NM_000212.3:c.187C>T

ClinVar: 631774 https://www.ncbi.nlm.nih.gov/clinvar/variation/631774/

CAID: CA8622892

gnomAD: PopMax = 0.00002555 https://gnomad.broadinstitute.org/variant/17-47283375-C-T?dataset=gnomad_r4

Gene: ITGB3

HGVS: NM_000212.3:c.505C>T

ClinVar: 953061 https://www.ncbi.nlm.nih.gov/clinvar/variation/953061/

CAID: CA291224658

gnomAD: PopMax = 2.800e-7 https://gnomad.broadinstitute.org/variant/17-47284586-C-T?dataset=gnomad_r4

Supplementary Table S1:

Case6: GT7, French, gender and age 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.187C>T (p.Arg63Cys) and NM_000212.2:c.505C>T (p.Arg169Ter)

LegacyVariant: N/A

ClinVar: 631774

CAiD: CA8622892 and CA291224658

gnomAD: MAF in the East Asian population is 0.00005012 https://gnomad.broadinstitute.org/variant/17-45360741-C-T