Supplementary Tables 1 and 2 combined information:

Case15a: Male, 15 years old, brother to GT15b

DiseaseAssertion: Glanzmann thrombasthenia

FamilyInfo: Available per Table 1, brother to GT15b

ParentalGenotype: Parents are not consanguineous, no other genotype information available

CasePresentingHPOs: HP:0000978, HP:0000979, HP:0031364, HP:0000421, HP:0000225

(Bruising, purpura, ecchymosis, epistaxis, gingival bleeding)

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Showed 10-20% of αIIbβ3 expression measured by flow cytometry

PlateletAggregation: Platelet aggregation showed no response to ADP, a small response to collagen but normal response to ristocetin

CasePreviousTesting: All exons from ITGA2B and ITGB3 genes were amplified by PCR using intronic primers. DNA sequencing was determined by Sanger sequencing.

Gene: ITGB3

Variant: NM_000212.2:c.1525del (p.Gln509Argfs*160) and NM_000212.2:c.1199G>A (p.Cys400Tyr)

LegacyVariant: N/A

ClinVar: 13562 (p.Cys400Tyr)

CAiD: CA915940237 (p.Gln509Argfs*160) and CA123244 (p.Cys400Tyr)

gnomAD: N/A