The distribution of blood genetic markers in immigrant Chinese populations.
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Acid Phosphatase↗
Biomedical subjects
B R Hawkins
Publications and source records attributed to B R Hawkins.
HLA class I and class II frequencies of a Hong Kong Chinese population based on bone marrow donor registry data.
HLA-A, and -B antigen, gene and haplotype frequencies have been calculated from 18,774 southern Chinese donors on a Hong Kong-based bone marrow donor registry. Two hundred and fifty donors were also tested for HLA-DRB1, -DQA1, and -DQB1 alleles using the PCR-SSP technique. Forty-one HLA-A, -B combinations showed statistically significant positive linkage disequilibrium at the 0.05 level after adjustment for the number of haplotypes theoretically possible and 43 showed significant negative disequilibrium. Thirty-nine different DRB1-DQA1-DQB1 haplotypes were identified of which 20 occurred 5 or more times. The most prevalent was DRB1*0901-DQA1*0301-DQB1*0303 (haplotype frequency = 0.1620). This is the first paper to report the distribution of DQA1*0104, DQA1*05011 and DQA1*05012/13 alleles in Chinese. These data are important for phylogenetic, comparative and medico-legal studies and are of particular value in estimating the likelihood of obtaining appropriately matched donors for Chinese patients awaiting bone marrow transplantation.
Bone Marrow Transplantation↗
Sibling HLA-matched cord blood transplant for beta-thalassemia: report of two cases, expression of fetal hemoglobin, and review of the literature.
PURPOSE: A program of cord blood stem cell (CBSC) transplants for patients with beta-thalassemia major was initiated in conjunction with the prenatal diagnostic service in 1994. Two patients who received HLA-matched related CBSC transplants with posttransplant fetal hemoglobin (HbF) expression are described and the literature is reviewed. PATIENTS AND METHODS: After screening 12 pregnancies, matched sibling CBSC transplants were performed for 2 girls with beta-thalassemia major when they were 3.8 and 2.2 years old, respectively. Their HbF was assayed serially. RESULTS: The nucleated cell counts/kg were 11.4 x 10(7) and 6.2 x 10(7), which engrafted on days 19 and 24, respectively. The children are now transfusion-independent at 3 years and 1.2 years posttransplant. Their HbF levels showed a rapid rise posttransplant and reached peak levels of 37.2% and 42.2% on day 83 and day 88, respectively. The HbF levels declined to 1.0% and 3.8% on day 581 and day 305, respectively. Nine other sibling CBSC transplants for thalassemias have been reported with an engraftment rate of approximately 50%. Graft rejection was related to insufficient CBSC number in one. CONCLUSIONS: HbF levels in patients with beta-thalassemia major after CBSC transplants could be influenced by many factors, including reactivation of HbF synthesis, intrinsic rate of Hb switching of CBSC, and mixed chimerism.
Female↗
A Chinese family with non-insulin-dependent diabetes of early onset and severe diabetic complications.
Non-insulin-dependent diabetes mellitus of early onset has recently been described in Caucasians as a distinct syndrome with a characteristic pedigree suggestive of inheritance of genetic determinants from both parents. It is characterized by absence of islet cell antibodies and the severity of its clinical course. We report a Chinese family pedigree of three generations in which this form of diabetes has affected the third generation. Some members of this pedigree had severe complications at presentation in their twenties.
Adolescent↗
Novel HLA-DR2-related haplotypes in Hong Kong Chinese implicate the DQB1*0602 allele in susceptibility to multiple sclerosis.
Multiple sclerosis (MS) is strongly associated with the HLA-Dw2 haplotype DRw15.DQw6 in Caucasoids, although the relative contributions of DR and DQ loci to disease susceptibility are unknown. The situation is further complicated by the apparent lack of an association between DR2 and MS in Orientals. This study examined 42 DR2-positive chromosomes in healthy Chinese and 12 DR2-positive chromosomes in MS patients from Hong Kong, using oligonucleotide hybridizations of DQA1, DQB1, DRB1, and DRB5 polymerase chain reaction (PCR) products. There was marked heterogeneity in DR2-related haplotypes in controls (ten types), where the most frequent haplotype, confirmed in one family, involved the novel arrangement DRB1*1501, DQB1*0601. Another common haplotype had the unusual combination of DRB1*1602, DRB5*0101 as confirmed by DNA sequencing of the DRB5 allele. In contrast, the most common DR2-related haplotype in MS patients was the 'classical' Dw2 haplotype DRB1*1501, DQB1*0602, with a frequency of 50% compared with 12% in controls (P = 0.01). Novel DR,DQ linkage disequilibrium relationship in Hong Kong Chinese have permitted recognition of DQB1*0602 as a susceptibility allele in DR2-positive MS patients, although a role for the DRB1*1501 allele in MS pathogenesis has not been excluded by this study.
Alleles↗
Distribution and co-occurrence of MHC class I, II, and III markers in southern Chinese: implications for autoimmune disease.
A study of MHC class I, II, and III markers in a group of southern Chinese in Hong Kong is reported. HLA antigen frequencies and complement allele frequencies are given, together with statistically significant pair-wise co-occurrences. Over half of the statistically significant positive and negative linkage disequilibria relate to two extended haplotypes. These haplotypes, or components of them, are associated with a number of diseases in Chinese, particularly diseases of autoimmune origin. One haplotype, A2, Bw46, DRw9, appears to be an analogue of the haplotype A1, B8, DR3 which predisposes to similar diseases in Caucasians. The question is raised of why susceptibility to the same group of diseases in two different racial groups should be related to the haplotypes having the strongest linkage disequilibria within those racial groups.
Asian People↗
The prevalence of ankylosing spondylitis among B27 positive normal individuals--a reassessment.
Previous workers reported symptomatic, but undiagnosed, ankylosing spondylitis (AS) in some 20% of blood donors with HLA B27. As part of an ongoing population study, we compared 139 B27 positive individuals with 128 controls and found no differences in spinal mobility or back pain. There were no differences when all available radiographs were compared. No case of AS was identified. It is concluded that AS occurs in far less than 20% of B27 positive individuals and that the prevalence of AS is of the order predicted by conventional epidemiological surveys. Although HLA typing can be helpful in excluding AS suspected on clinical grounds, it cannot be used to confirm the diagnosis.
Adult↗
Host factors and susceptibility to influenza A infection: the effect of ABO blood groups and HL-A antigens.
The effect of two host genetic factors on the outcome of influenza A infections has been examined, ABO blood groups and HL-A antigens. A significantly higher proportion of blood group B subjects was found to have serological evidence of infection with epidemic influenza despite a high incidence of residual antibody among the volunteers. No difference was observed in the ability of subjects of different blood groups to seroconvert after receiving two doses of live attenuated influenza A vaccine, but a significantly higher proportion of blood group A vaccines seroconverted after receiving their first dose of vaccine. The association between HL-A type BW16 and resistance to infection with influenza could not be confirmed. The results are discussed in terms of an indirect association between susceptibility to influenza infection and the two host genetic factors.
ABO Blood-Group System↗