Human platelet-specific antigens (HPAs) are found on platelet membrane glycoproteins and are the target of platelet alloantibodies that mediate platelet destruction in neonatal alloimmune thrombocytopenia (NAIT), post-transfusion purpura (PTP) and refractoriness to platelet transfusion therapy. The biallelic polymorphism of all HPA systems is known to be due to a substitution of a single base pair. This study was performed to investigate the frequency of the HPA genes in Koreans, based on these substitutions. The genotypes of eight HPA systems were determined by polymerase chain reaction using sequence-specific primers (PCR-SSP) for HPA-1, -2, -4, -5, and -8 and restriction fragment length polymorphism (RFLP) for HPA-3, -6, and -7. The gene frequencies obtained from 200 unrelated Koreans were 0.99 and 0.01 for HPA-1a and -1b, 0.92 and 0.08 for HPA-2a and -2b, 0.55 and 0.45 for HPA-3a and -3b, 0.99 and 0.01 for HPA-4a and -4b, 0.98 and 0.02 for HPA-5a and -5b, and 0.98 and 0.02 for HPA-6a and -6b. All the individuals tested were homozygotes for HPA-7a and HPA-8a. It has been reported that the HPA-1b antigen is extremely rare (less than 0.3%) in Oriental populations, but this study suggests that the frequency of this antigen in Koreans (2.0%) is higher than in Japanese and Chinese populations.

SummaryFibrinogen Matsumoto I is a novel hereditary dysfibrinogen identified in a 1-year-old boy with Down’s syndrome. Though he showed no apparent bleeding or thrombotic tendency, he had a congenital heart disease. Preoperative coagulation tests of his plasma revealed a prolonged thrombin time and the fibrinogen level determined by the thrombin time method was markedly decreased. Molecular weight of fibrinogen chains showed apparently normal Aα, Bβ-, and γ-chains. The rate of fibrinopeptide release was normal, whereas fibrin polymerization was delayed. Fibrinogen γ-chain gene fragments from the propositus were amplified by polymerase chain reaction then sequenced. The triplet GAT, coding for the amino acid residue γ364, was replaced by CAT, resulting in the substitution of Asp→His. This residue is adjacent to the Tyr-363 that is demonstrated to be the primary site for fibrin polymerization. Our results indicate that the residue γ364 Asp is essential for normal polymerization of fibrin monomer.

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We report a family with familial amyloid polyneuropathy (FAP), showing an early-onset and a fatal outcome before age 30. Transthyretin (TTR) gene analysis showed one point mutation (T-->C change) in the second base of codon 55, and the corresponding amino acid substitution of proline (Pro) for leucine (Leu) was confirmed at the protein level. This is the first FAP family of Taiwanese origin demonstrating a causative gene abnormality, and FAP with TTR-Pro55 was considered to be more serious compared with other forms of FAP.

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