Mongoloid

Abstract: Aims To investigate the frequency of the single nucleotide polymorphism C3435T in exon 26 of the MDR1 gene in Asians and to determine the functional significance of this SNP with the clinical pharmacokinetics of oral cyclosporin (Neoral) in 10 stable heart transplant patients. Methods The MDR1 C3435T polymorphism was investigated in 290 healthy Asian subjects (98 Chinese, 99 Malays and 93 Indians). We also compared the MDR1 polymorphism between the Asian population studied here and the published data on Africans and Caucasians. The clinical relevance of this SNP on oral bioavailability of a known P-gp substrate, cyclosporin, was assessed in 10 stable Chinese heart transplant patients. Results The homozygous TT genotype was observed in 32%, 28% and 43% of Chinese, Malays and Indians. The homozygous CC genotype was found in 25% of Chinese and Malays compared with 18% of Indians. The Indians had a lower frequency of the C allele [0.38 (0.31–0.45)] compared with the Chinese [0.46 (0.39–0.53)] and Malays [0.48 (0.42–0.55)]. Chi-squared test showed that the distribution of allele frequencies between the Malays and Indians differed significantly (P = 0.04). In this Asian population, the overall distribution of genotypes (CC, CT and TT) and allele frequencies were significantly different from those in Africans (P < 0.001). The results were also significant when the Chinese, Malays and Indians were compared separately with the African group (P < 0.001). Compared with the Caucasian data, the overall distribution of genotype and allele frequencies in the Asian population were also significantly different (P ≤ 0.05). However, when each Asian ethnic group was compared separately with the Caucasians, only the Indians were found to be significantly different (P ≤ 0.004). Genotypic–phenotypic correlations of this SNP were assessed in 10 stable Chinese heart transplant patients. The median AUC(0,4 h) was 11% lower in patients with CC genotype compared with subjects with TT genotype. However, the interpatient variability in AUC(0,4 h) was high in patients, especially in those with CC genotype. Conclusions The distribution of the SNP C3435T in exon 26 in the Chinese and Malay population was found to be similar to the Caucasians whereas the Indians were different. The Asian population also differed significantly from the African and Caucasian population in the distribution of the C3435T SNP. The low frequency of the T allele in the Indian population implies lower expression of P-gp and may have important therapeutic and prognostic implications for use of P-gp dependent drugs in individuals of Indian origin.

Abstract: This paper reports the distribution of immunoglobulin Gm and Km allotypes in 74 Chinese geographical populations. These populations are derived from 24 nationalities comprising 96.6% of the total population of China. A total of 9,560 individuals were phenotyped for Gm(1,2,3,5,21) factors, and 9,611 were phenotyped for Km(1). Phylogenetic trees were constructed on the basis of Gm haplotype frequencies and genetic distances. The results of cluster analysis show the heterogeneity of the Chinese nation, and confirm the hypothesis that the modern Chinese nation originated from two distinct populations, one population originating in the Yellow River valley and the other originating in the Yangtze River valley during early neolithic times (3,000–7,000 years ago). Frequencies of the Gm haplotype of 74 Chinese populations were compared with those of 33 populations from major racial groups. The results suggest that during human evolution, the Negroid group and Caucasoid-Mongoloid group diverged first, followed by a divergence between the Caucasoid and Mongoloid. Interrace divergence is high in comparison with intrarace divergence. There appear to be two distinct subgroups of Mongoloid, northern and southern Mongoloid. The northern and southern Mongoloid have Gm1;21 and Gm1,3;5 haplotypes as race-associate markers, respectively. Furthermore, the Caucasian-associated haplotype Gm3;5 was found in several of the minorities living in the northwest part of China. The presence of the Gm3;5 haplotype is attributed to the Caucasians living in Central Asia throughout the Silk Road. The amount of Caucasian admixture has been estimated. In contrast to the Gm haplotype distribution, Km1 gene frequencies showed a random distribution in the populations studied.

Abstract: Nasopharyngeal cancer is very common among the Chinese in various parts of the world, particularly Southern China, and frequent in certain other Mongoloid groups in Southeast Asia. Also, the incidence among the Eskimos of the western Canadian Arctic and Alaska is considerably higher than would be expected. This paper reports for the first time the incidence of nasopharyngeal cancer among native Greenlanders, an Eskimo population with some admixture of Caucasian blood. During 1955–1976, thirty-five cases of nasopharyngeal cancer were diagnosed. Ninety-four per cent (33 cases) were squamous cell carcinomas, including lymphoepitheliomas. Incidence rates 1965–1976, age adjusted to the “world” population distribution, were 12.3 and 8.5 per 100,000 per annum for males and females respectively. These rates are among the highest recorded in the world and significantly higher than among the Caucasian population in Denmark. Compared with other high risk populations nasopharyngeal cancer among Greenlanders had an older age distribution and a lower male-to-female sex ratio. An additional 11 cases with malignant involvement, seemingly confined only to cervical lymph nodes, may have included some undiagnosed nasopharyngeal cancers. Thus the calculated incidence rates of this study could represent only minimum rates. Further research is needed especially with regard to the HL-A profile and to possible traces of Epstein-Barr virus infection.

Abstract: Since the discovery in 1966 of the Gm ab3st gene, which characterizes Mongoloid populations, the distribution of allotypes of immunoglobulins (Gm) among Mongoloid populations scattered from Southeast Asia through East Asia to South America has been investigated, and the following conclusions can be drawn: 1. Mongoloid populations can be characterized by four Gm haplotypes, Gm ag, axg, ab3st, and afb1b3, and can be divided into two groups based on the analysis of genetic distances utilizing Gm haplotype frequency distributions: the first is a southern group characterized by a remarkably high frequency of Gm afb1b3 and a low frequency of Gm ag, and the second, a northern group characterized by a high frequency of both Gm ag and Gm ab3st but an extremely low frequency of Gm afb1b3. 2. Populations in China, mainly Han but including minority nationalities, show remarkable heterogeneity of Gm allotypes from north to south and contrast sharply to Korean and Japanese populations, which are considerably more homogenous with respect to these genetic markers. The center of dispersion of the Gm afb1b3 gene characterizing southern Mongoloids has been identified as the Guangxi and Yunnan area in the southwest of China. 3. The Gm ab3st gene, which is found with its the highest incidence among the northern Baikal Buriats, flows in all directions. However, this gene shows a precipitous drop from mainland China to Taiwan and Southeast Asia and from North to South America, although it is still found in high frequency among Eskimos, Koryaks, Yakuts, Tibetans, Olunchuns, Tungus, Koreans, Japanese, and Ainus. On the other hand, the gene was introduced into Huis, Uyghurs, Indians, Iranians, and spread as far as to include Hungarians and Sardinians in Italy. On the basis of these results, it is concluded that the Japanese race belongs to northern Mongoloids and that the origin of the Japanese race was in Siberia, and most likely in the Baikal area of the Soviet Union.