The Southeast Asian 12.5 KB (delta-beta) degrees-deletion: a common beta-thalassemia in Mon-Khmer groups (Lao Theung) of South Laos.

Seven patients with unexplained anemia and mild thalassemic features were ascertained during a survey of hemoglobinopathies in the Sekong Province in South Laos. These patients belong to the Austroasiatic (Mon-Khmer) population of South Laos (official designation Lao Theung). Hemoglobin electrophoresis on cellulose acetate showed absence of Hb A and two bands in the positions of Hb E and Hb F respectively.

The 'hot-spot' of Hb E [beta26(B8)Glu-->Lys] in Southeast Asia: beta-globin anomalies in the Lao Theung population of southern Laos.

Hb E [beta26(B8)Glu-->Lys], is the most common abnormal hemoglobin (Hb) in Southeast Asian populations. The hitherto highest frequencies of the Hb E gene (HBB*E) in large population samples, approximately 0.3, were observed in the southern part of northeastern Thailand.

Prenatal diagnosis of hemoglobin Bart's hydrops fetalis by HPLC analysis of hemoglobin in fetal blood samples.

Since HbF and HbA are not found in fetuses with Hb Bart's hydrops fetalis the feasibility of prenatal diagnosis of homozygous alpha-thalassemia 1 by fetal hemoglobin typing was examined. Blood samples were obtained from fetuses at 18 to 22 weeks of gestation by cordocentesis in 32 pregnant women at risk of having a child with homozygous alpha-thalassemia 1 (alpha-thal-1). The samples were analyzed by a PCR-based method for the diagnosis of alpha-thal-1 (SEA type) and the proportion of hemoglobin fractions were determined by automated HPLC.

Prenatal diagnosis of beta-thalassemia major by high-performance liquid chromatography analysis of hemoglobins in fetal blood samples.

In Thailand and adjacent countries, most of the beta-thalassemia genes are beta(0)-thalassemia mutations that prevent the production of Hb A. We propose the quantitation of the Hb A fraction in fetal blood in the mid-trimester of pregnancy by automated high performance liquid chromatography as a reasonable prenatal diagnostic method to be applied in areas with limited laboratory facilities. Forty pregnant women at risk of delivering a child with beta-thalassemia major were identified using an erythrocyte osmotic fragility test and quantitation of Hb A2.

Beta-thalassemia in the German population: mediterranean, Asian and novel mutations. Mutations in brief no.228. Online.

The beta-thalassemia mutations of 13 unrelated heterozygous Germans who remained unidentified in a previous study of 40 subjects were investigated at the DNA level. Two Mediterranean, one Asian and three novel mutations (CD6 -G, CDs 108 /112-12nt, CDs 130/131 + GCCT) were identified. Altogether, in 30 of the 35 subjects (86%) in which a mutation in the beta-globin gene was identified, the mutation was of Mediterranean origin.

Prevalence of alpha-thalassemias in northern Thailand.

The population of northern Thailand has one of the highest frequencies of alpha-thalassemia in the world. However, the available distributional data are controversial. In addition to deletional types of alpha-thalassemia Hb, type Constant Spring should also be taken into consideration in alpha-thalassemia population studies, because it causes clinical alpha-thalassemia in the homozygous state or when present with both alpha-globin genes deleted in trans.

Hemoglobin E and codon 17 nonsense: two beta-globin gene mutations common in Southeast Asia detected by the use of ARMS.

Hemoglobin E (codon 26 GAG-->AAG) and codon 17 nonsense (AAG-->TAG), two clinically important mutations of the beta-globin gene, are common in Southeast Asia. The detection of these mutations using allele-specific PCR is described. Together with the previously reported method for the detection of the common Southeast asian codon 41-42 frameshift mutation (del CTTT), it is possible to identify the vast majority of clinically important beta-globin gene mutations in Southeast Asian populations by means of nonradioactive methods.

[Genetic traits in the area of Bodrogköz].

In 1984 a late malaria endemic area, called Bodrogköz was studied. This was a reexamination of the population genetic work performed by Walter, Nemeskéri. In six villages of Bodrogköz 328 persons were tested for AB0, Rh blood groups, haptoglobins, haemoglobin concentration, haematocrit, erythrocyte amount, the MCV, the MCH and the G-6-PD were analyzed.

Mediterranean types of beta-thalassemia in the German population.

Forty beta-thalassemia genes from unrelated German heterozygotes with no known foreign ancestry were examined using the oligonucleotide technique and DNA restriction analysis, with the aim of determining the contribution of Mediterranean beta-thalassemia mutations to the prevalence of this trait in the German population. Of the 40 beta-thalassemia genes, 26 were identified as Mediterranean types (20 beta 39 nonsense, 3 IVS2 nt 110, 2 IVS2 nt1, 1 IVS1 ntl G----A). The geographic distribution of the birthplaces of the probands' grandparents revealed no difference in the proportion of Mediterranean and unidentified beta-thalassemia genes in the west and the north of Germany.

Direct demonstration of the HB Suan-Dok mutation in the alpha 2-globin gene by restriction analysis with Sma I.

Hb Suan-Dok [alpha 2(109)(G16)Leu-greater than Arg beta 2] has an alpha-thalassemia-like effect due to low production and instability of the altered alpha-globin chain. Since the Hb Suan-Dok mutation (CTG-greater than CGG) creates a new Sma I restriction site, it was possible to diagnose the mutation by restriction analysis. The location in the alpha 2-globin gene was confirmed.

Study of alpha-thalassemia in northeastern Thailand at the DNA level.

The frequency of alpha-thalassemias in a general population sample from northeastern Thailand and in an Austroasiatic group with high frequencies of hemoglobin E and beta-thalassemia, the So, was estimated using DNA techniques. Among 64 healthy adult subjects from the Khonkaen and Ubol areas, the following haplotype frequencies were determined: alpha alpha, 0.742; -alpha 3.

The distribution of the Hb constant spring gene in Southeast Asian populations.

The distribution of the hemoglobin Constant Spring (Hb CS) gene in eight populations in Southeast Asia (including Assam) was determined using oligonucleotide hybridization. Hb CS was absent in two Assamese populations with a high prevalence of Hb E. The Hb CS gene frequency was 0.

Beta zero-thalassemia in a Thai family is caused by a 3.4 kb deletion including the entire beta-globin gene.

DNA analysis of a Northern Thai family with a child affected with beta-thalassemia major revealed a novel deletion of 3.4 kb removing the entire beta-globin gene in the proposita and her mother. Detailed mapping of the deletion located the 5' breakpoint in the region between nucleotides -810 and -128 of the beta-globin locus, and the 3' breakpoint between the Ava II and Xmn I sites located downstream of the beta-globin gene.

The spectrum of beta-thalassemia mutations in northern and northeastern Thailand.

A total of 123 beta-thalassemia genes from northern (n = 113) and northeastern (n = 10) Thailand were examined. Using five oligonucleotide probes, the mutation in 108 genes (88%) was identified: 50 nonsense 17, 49 frameshift 41-42, 4-28(A----G), 2 IV1 nt5(G----C), 2IVS2 nt654, and 1 deletion removing the entire beta-globin gene. The nonsense 17 mutation (n = 39) was linked to a single haplotype, whereas the frameshift 41-42 mutation occurred with several haplotypes.

Beta-globin gene linked DNA haplotypes and frameworks in three South-East Asian populations.

DNA haplotypes and frameworks (numbers in parenthesis) linked to the beta-globin gene were determined by restriction fragment analysis using eight restriction endonucleases on 86 (97) chromosomes bearing the normal beta-globin gene (HBB*A) and 108 (118) chromosomes bearing HBB*E in subjects homozygous for HBB*A or HBB*E from three South-East Asian populations with high HBB*E frequencies (northern Thailand, north-eastern Thailand and Cambodia). A systematic nomenclature for beta-globin gene-linked haplotype characterized by six polymorphic sites is introduced. In all populations, HBB*A occurred preferentially (greater than 80%) in linkage with the haplotype 41 (+----+) and all three frameworks described by Antonarakis et al.

Frequency of deletional types of alpha-thalassemia in Kampuchea.

The frequency of deletional types of alpha-thalassemias in the Khmer population of Kampuchea (Cambodia) was estimated using DNA techniques. Among 58 healthy adult Kampucheans from rural areas, 17 had alpha-globin gene anomalies. There were 14 heterozygotes and two homozygotes for alpha(+)-thalassemia; the remaining test subject carried a deletion of both alpha-globin genes (alpha(0) -thalassemia of the Southeast Asian type) on one chromosome 16, and triple alpha-globin genes on the other.

DNA haplotypes and frameworks associated with the beta-globin gene in the Kachari population of Assam (India).

DNA haplotypes and frameworks associated with the beta-globin gene were determined in a Tibeto-Burman group, the Kachari, from Upper Assam, India, using restriction analysis at eight restriction sites. Of the total of 59 subjects, 26 were homozygous for HBB*A and 33 homozygous for HBB*E. Complete haplotype determination in 33 subjects revealed a conspicuous difference in haplotype distribution between HBB*A- and HBB*E-bearing chromosomes.

Alpha-thalassemia in northern Thailand. Frequency of deletional types characterized at the DNA level.

The frequency of alpha-thalassemias in northern Thailand was estimated using DNA techniques. Among 106 healthy adult Thais from the Chiangmai area, 28 were shown to carry alpha-globin gene anomalies. There were 19 heterozygotes and 1 homozygote for alpha-thalassemia-2.

The hemoglobin E belt at the Thailand-Kampuchea border: ethnic and environmental determinants of hemoglobin E and beta-thalassemia gene frequencies.

The frequencies of the hemoglobin E gene (HBB*E) and the beta-thalassemia gene(s) (HBB*T) were determined in 890 healthy adult males from three areas at the Thai-Kampuchean border in Northeastern Thailand. The population of the three study areas differs ethnically: area I is inhabited by Khmer-speaking people, area II has an ethnically mixed population (Tai-Lao, Soui and Khmer), and area III is predominantly Lao. In view of the topographic differences in malaria endemicity in the pre-eradication era, the probands from the three study areas were divided into subgroups "hills" and "plains" according to the location of their home villages.

X-chromosomally inherited split-hand/split-foot anomaly in a Pakistani kindred.

A Pakistani kindred comprising seven generations and 36 members with the split-hand/split-foot anomaly is described. The full expression of the trait, monodactylous or split hand and split foot, mainly of the lobster-claw type, was present in 33 males and 3 females. Other females showed a distinctly milder expression of the trait, usually in the form of partial syndactyly, metacarpal and phalangeal hypoplasia, and malformation.

Distribution of hemoglobin E and beta-thalassemia in Kampuchea (Cambodia).

The hemoglobin type of 360 adult Cambodian subjects was determined by cellulose acetate electrophoresis and microcolumn chromatography. The following distributions and frequencies of the Hb E (beta E) and the beta-thalassemia (beta-thal) genes were found: in a group of 264 Cambodians of rural areas 153 Hb A, 83 Hb AE, 19 Hb E, and nine beta-thalassemia minor (frequency beta E 0.2292, beta-thal 0.