Case1: Female, 35 years old, Italian

DiseaseAssertion: Macrothromocytopenia

FamilyInfo: See Supp. Fig S1 for pedigree

ParentalGenotype: See Supp. Fig S1 for pedigree

CasePresentingHPOs: N/A

CaseHPOFreeText: Life-long moderate to severe bleeding, mainly mucocutaneous

CaseNotHPOs: N/A

CaseNotHPOsFreeText: No abnormalities in blood clotting

ProteinExpression: Flow cytometry showed mild reduction of surface αIb β3

PlateletAggregation: Impaired platelet aggregation to physiological agonists but not to ristocetin,

CasePreviousTesting: ITGA2B and ITGB3 were amplified and sequenced

Gene: ITBG3

Variant: NM_000212.2:c.2134+1G>C

LegacyVariant: N/A

ClinVar: 50228

CAiD: CA143711

gnomAD: N/A

Case1: Patient PDJ (found in GT database as well) 57 years old, ethnicity not specified

DiseaseAssertion: Thrombocytopenia

FamilyInfo: N/A

ParentalGenotype: N/A

CasePresentingHPOs: N/A

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Quantitative analysis of GPllb-llla surface expression showed only 20,000 GPllb-llla receptors/platelet, approximately half of the value obtained with control platelets

PlateletAggregation: N/A

CasePreviousTesting: DNA sequence analysis of the GPIIIa gene was performed

Gene: ITGB3

Variant: NM_000212.2:c.709_710del

LegacyVariant: N/A

ClinVar: N/A

CAiD: CA8623029

gnomAD: MAF in the European (non-Finnish) population is 0.00001796 https://gnomad.broadinstitute.org/variant/17-45363717-CAG-C

Case2: Male, 9 years old, Japanese

DiseaseAssertion: Macrothrombocytopenia

FamilyInfo: Information on mother is given (minimal other family information)

ParentalGenotype: Mother: ITGA2B (Phe993del heterozygous)

CasePresentingHPOs: N/A

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Surface expression of αIIbβ3 in platelets of the patient and his mother was about 80% compared to control subjects with an increase of CD42b expression

PlateletAggregation: N/A

CasePreviousTesting: The entire coding sequence of exons and exon-intron boundaries of ITGA2B and ITGB3 and the whole coding regions of ITGA2B and ITGB3 cDNA obtained from platelets were sequenced as previously described. In the case of ITGA2B p.Phe993del, PCR products obtained from amplification of exon 30 of ITGA2B from the patient's DNA were subcloned to pCR2.1-TOPO and sequence analysis was performed

Gene: ITGA2B

Variant: NM_000419.3:c.3070_3072del (p.Phe1024del)

LegacyVariant: p.Phe993del legacy nomenclature

ClinVar: N/A

CAiD: CA8602460

gnomAD: N/A

Case3: Female, 8 years old, Japanese

DiseaseAssertion: Thrombocytopenia

FamilyInfo: Information on mother and grandfather available in Table 1(minimal information on other family members)

ParentalGenotype: Mother: ITGB3 (p.Asp621_Glu660del heterozygous) See Table 1

CasePresentingHPOs: HP:0000978 (Bruising)

CaseHPOFreeText: Subaponeurotic hematoma

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: Surface expression levels of αIIbβ3 in platelets of patient were decreased to around 65% of normal subjects with increase of CD42b (See Table 1)

PlateletAggregation: N/A

CasePreviousTesting: Sequence analysis of DNA revealed the patient's mutation. RT-PCR was also performed. The entire coding sequence of exons and exon-intron boundaries of ITGA2B and ITGB3 and the whole coding regions of ITGA2B and ITGB3 cDNA obtained from platelets were sequenced.

Gene: ITGB3

Variant: NM_000212.2:c.2134+1G>A (p.Asp621_Glu660del)

LegacyVariant: N/A

ClinVar: N/A

CAiD: CA400033344

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

Case2:

DiseaseAssertion: Glanzmann Thrombesthenia and Macrothrombocytopenia (MTP)

FamilyInfo: Case1 (his older sister) and no parental information.

ParentalGenotype: N/A

CasePresentingHPOs: HP:0000421, HP:0011877

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOsFreeText: N/A

ProteinExpression: No information for the brother on protein expression.

CasePreviousTesting: As a part of an initial testing of this patient's gene panel (not specified which genes), DNA from this patient was submitted to ThromboGenetics in Cambridge UK. While confirming the two ITGB3 mutations described, an additional finding was a heterozygous mutation in TUBB1.

Gene: ITGB3

Variant: NM_000212.2:c.565C>T and NM_000212.2:c.629G>C

LegacyVariant: N/A

ClinVar: 2890

CAiD: CA291224669 and CA400023389, respectively as written in variant section.

gnomAD: Maximum allele frequency for the variant NM_000212.2:c.565C>T: 0.00002638 https://gnomad.broadinstitute.org/variant/17-45362012-C-T