Table 1.

Characteristics of the patients with congenital P2Y₁₂ deficiency

Patient identification [reference]	P2Y12 mutations	Binding sites for 2MeS-ADP	Platelet aggregation induced by ADP ≥ 10 μM	Bleeding time (min)	History of abnormal bleeding
VR [26, 34]	p.[Gln98fs] + [Gln98fs]	Severely reduced	Reduced and reversible	15; 20	Yes
ML [28, 36]	p.[Phe240fs] + [?]a	Severely reduced	Reduced and reversible	>20	Yes
IG [29, 35]	p.[0] + p.Thr126fsc	Severely reduced	Reduced and reversible	>30	Yes
MG [29, 35]	p.[0] + p.Thr126fsc	Severely reduced	Reduced and reversible	20	Yes
OSP-1 [30]	p.[0] + [0]b	NA	Reduced and reversible	>15	Yes
?? [31]	p.[Gly12fs] + [Gly12fs]	NA	Reduced and reversible	NA	Yes
CL [28, 36]	p.[Phe240fs] + [=]	Intermediate	Full and irreversible	NA	No
GL [29, 35]	p.[0] + [=]c	Intermediate	Full and irreversible	13	No

Patient CL is the daughter of patient ML; patient GL is the son of patient MG who is the sister of patient IG

The upper normal limit of the bleeding time varies between 8 and 10 min in different laboratories

NA not available

^aNo mutations were found in one allele of patient ML; however, the findings that the patient’s platelets contained P2Y₁₂ transcripts derived from the mutant allele only and that his daughter (CL) inherited the mutant allele from her father and a normal allele from her mother, suggest that patient ML has an additional, as yet unknown mutation that silences his normal allele (see text for details)

^bFailure of expression of the P2Y₁₂ protein (p.[0]) in patient OSP-1 was associated with homozygous single nucleotide substitution in the transduction initiation codon (ATG to AGG)

^cp[0] was associated with partial or complete P2Y₁₂ gene deletion in patients IG, MG and GL