DNA diagnosis of single gene disorders in patients of non-European origin: experience from Kuwait.

OBJECTIVE: The aim of this study was to establish genetic DNA-diagnostic service in Kuwait. METHODS: Polymerase chain reaction, restriction fragment length polymorphisms, heteroduplex analysis and DNA sequencing were applied. RESULTS: Direct testing for common mutations had variable success in Kuwaiti patients with different genetic disorders, and additional mutation analysis was required in many cases. Genetic heterogeneity, mutations of Mediterranean, African and Arabic/Middle Eastern origin, and homozygosity by descent are characteristic of patients from Kuwait. CONCLUSIONS: More efforts aimed at the identification of mutations underlying genetic disorders in Kuwait as well as in other Gulf countries are warranted. This can be achieved by focusing genetic research in the academic institutions of Gulf countries towards this goal.

Frequencies of SDF-1 chemokine, CCR-5, and CCR-2 chemokine receptor gene alleles conferring resistance to human immunodeficiency virus type 1 and AIDS in Kuwaitis.

The frequencies of three mutations conferring resistance to HIV/AIDS were determined in a population sample of native Kuwaitis. The CCR2-641, SDF1-3'A, and CCR5-m303 mutations were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) tests using restriction endonucleases Bsa BI, Msp I, and Hinc II, respectively. The frequency of the mutant alleles were: for CCR2-641, 0.1195 (95% CI 0.0801-0.1694); for SDF1-3'A, 0.2593 (95% CI 0.2024-0.3231), and for CCR5-m303, less than 0.0025. Thus, the CCR2-641 and especially SDF1-3'A mutations are sufficiently common in Arabs and can be used for prognostic genotyping in HIV-infected individuals from the Gulf countries.

Population study of common glucose-6-phosphate dehydrogenase mutations in Kuwait.

DNA samples from 206 unrelated Kuwaitis of both sexes, i.e. 200 randomly selected individuals and 6 glucose-6-phosphate-dehydrogenase (G6PD)-deficient probands, have been analyzed by the PCR/RFLP technique for mutations underlying the most common G6PD-deficient variants (Mediterranean and A-). At the first step all samples were studied for the 563C-->T and 376A-->G mutations, then the samples positive for 376A-->G were further analyzed for 202G-->A, 680G-->T and 968T-->C mutations. Three mutations (563C-->T, 376A-->G and 202G-->A) were found to be present in the Kuwaiti population at polymorphic frequencies (0.0503, 0.0215 and 0.0111, respectively). Nineteen out of 20 unrelated Kuwaiti chromosomes with 563C-->T had Mediterranean haplotype as judged by 1311C-->T polymorphism. The frequency of G6PD-deficient genotypes was 4.5% (5.73% in males and 2.56% in females).

A survey for 32 nucleotide deletion in the CCR-5 chemokine receptor gene (deltaccr-5) conferring resistance to human immunodeficiency virus type 1 in different ethnic groups and in chimpanzees.

The 32 nucleotide deletion in the CCR-5 chemokine receptor gene referred to as deltaccr-5 has been shown to confer resistance to HIV-1. Using PCR, 1,105 human subjects and 33 common chimpanzees were genotyped attributing them to one of the three possible genotypes: wild-type homozygote (w/w); deltaccr-5 homozygote (deltaccr-5/deltaccr-5) and deltaccr-5/wild-type heterozygotes (deltaccr-5/w). The ethnic groups investigated included different Middle Eastern nationalities (mainly Arab) and Russians. Carriers of the deltaccr-5 mutation were found among Arabs, Iranians and Russians. The highest frequency of the mutation was seen in Russians (24.4% of the deltaccr-5 heterozygotes, allele frequency-0.1221). Surprisingly, the only deltaccr-5 homozygote identified in our study was an Egyptian. The origin of the deltaccr-5 mutation in the Middle Eastern populations, both Arab and non-Arab, is most probably due to a gene flow from the Europeans. The frequency of the deltaccr-5 mutation in Russians is one of the highest known. It might be one of the factors contributing to a relatively slow pace of increase in the incidence of sexually acquired HIV infection in Russia. None of the chimpanzees tested was positive for deltaccr-5. Interestingly, the DNA sequence of the chimpanzee CCR-5 gene in the region including the site of the deltaccr-5 mutation, and flanking areas, was virtually identical to the homologous human sequence, only two mismatches (silent substitutions) were found.

Phylogenetic analysis of simian T-lymphotropic virus Type I (STLV-I) in common chimpanzees (Pan troglodytes): evidence for interspecies transmission of the virus between chimpanzees and humans in Central Africa.

Serum and peripheral blood leukocytes from the chimpanzees (Pan troglodytes) of the colony of the Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, NIH, were tested for the presence of STLV-I-specific antibodies and proviral DNA. Antibodies were determined by gelatin particle agglutination and Western blot (WB) assays utilizing HTLV-I antigens. Proviral DNA was detected by four PCR assays targeting three different regions of STLV-I genome: the fragments of the env and pol genes and LTR. Twenty of twenty-two DNA samples from WB-positive animals were PCR positive. None of the DNA samples from WB-negative (n = 5) and WB-indeterminate (n = 4) animals was PCR positive. The results of the nested and double nested env PCR tests were fully concordant; the seminested LTR PCR test was much less sensitive. The DNA sequences from the env (483 bp) and the pol (200 bp) genes and LTR (705 bp) were determined for six, two, and two chimpanzee STLV-I isolates, respectively. Phylogenetic analysis revealed that chimpanzee STLV-I isolates can be attributed to three clades. The first of these clades (SS-PTR1/CSA) included STLV-I isolates from the chimpanzees and West African subspecies of African green monkeys (Cercopithecus a. sabaeus). The other clades (S-PTR2 and S-PTR3) included STLV-I isolates only from chimpanzees. However, both S-PTR2 and S-PTR3 clustered together with Central African HTLV-I comprising the human/simian clade (HS-HSA/PTR). This pattern of phylogenetic clustering suggests that interspecies transmission of STLV-I occurred between chimpanzees and African green monkey subspecies as well between chimpanzees and human populations in Central Africa.

TaqI polymorphism in the 3' flanking region of the PI gene among Kuwaiti Arabs and Russians.

The Taq1 polymorphism in the 3' flanking region of the PI gene has been reported to be associated with chronic obstructive pulmonary disease (COPD). We have studied the frequency of the Taq1 polymorphism in 117 Kuwaiti Arabs and 110 Russians using PCR/RFLP. The frequency of this polymorphism was found to be 0.235 in the Arabs and 0.027 in the Russians. Such a striking difference in allele frequencies could be due to a 'founder effect' in the Kuwaiti population. However: it may also be that this mutation provides a selective advantage, thus accounting for its fixation at a rather high frequency in some populations. Our results suggest that ethnic composition is a very important factor which should be taken into consideration when studying the association of the Taq1 polymorphism with COPD.

Simian T-lymphotropic virus type 1 (STLV-1) infection in wild yellow baboons (Papio hamadryas cynocephalus) from Mikumi National Park, Tanzania.

Serum and peripheral blood leukocytes from wild yellow baboons (Papio hamadryas cynocephalus) were tested for the presence of STLV-1-specific antibodies and proviral DNA. Fourteen of 30 sera tested positive by radioimmunoprecipitation assay (RIPA) with HTLV-1. Among 36 DNA samples tested by PCR 15 were positive by double nested PCR for a fragment of the STLV-1 env gene, the most sensitive assay among PCR tests employed. Of 30 animals that were tested both serologically and by PCR in only 1 case were the results discordant (PCR-positive, antibody-negative). The DNA sequences from env (378 bp), pol (212 bp), and LTR (705 bp) were determined for 5, 5, and 2 Mikumi STLV-1 isolates, respectively. The DNA sequences of Mikumi STLV-1 isolates were virtually identical and phylogenetic analysis revealed that they were clearly distinct from previously published baboon STLV-1 sequences, including those STLV-1 isolates presumed to be from yellow baboons. The results of this study suggest that reliable placement of individual STLV-1 within the PTLV-1 phylogeny requires genomic sequences of STLV-1 isolates from wild animals whose taxonomic identity and geographical origin are firmly established and that the LTR is the genomic region of STLV-1 which is the most informative for cladistic analysis of these viruses.

Deletion analysis of the SMN and NAIP genes in Kuwaiti patients with spinal muscular atrophy.

Two genes are known to be involved in spinal muscular atrophy (SMA), namely, SMN (survival motor neuron) and NAIP (neuronal apoptosis inhibitory protein). Deletion analysis of these genes has been reported for many ethnic groups. We have extended this analysis to include 15 Arabic patients (11 unrelated cases of type I, which represent practically all of the patients diagnosed within the last 2 years in Kuwait, and 4 type-II cases from a single kinship). Also, 41 healthy relatives (parents and sibs) and 44 control individuals of Arabic origin were analyzed. The homozygous deletions of exons 7 and 8 of the SMN gene were found in all SMA patients studied. Exon 5 of NAIP was homozygously absent in all type-I patients, but was retained in type-II cases. Among members of SMA families, one mother was found to be homozygously deleted for NAIP. All of the control individuals had both normal SMN and NAIP. Our results are in agreement with the general consensus that the incidence of NAIP deletion is higher in the more severe SMA cases. Furthermore, they suggest that SMA type-I chromosomes, with the dual deletion of the SMN and NAIP genes, are more common in Arabs than in patients of other ethnic origin.

Interspecies transmission of macaque simian T-cell leukemia/lymphoma virus type 1 in baboons resulted in an outbreak of malignant lymphoma.

An outbreak of malignant lymphoma has been observed in one of the baboon (Papio hamadryas) stocks of Sukhumi Primate Center. More than 300 cases in this "high-lymphoma stock" have been registered since 1967. Human T-cell lymphotropic virus type 1 (HTLV-1)-related virus was implicated as the etiologic agent of Sukhumi baboon lymphoma. The origin of this virus remained unclear. Two possibilities were originally considered: the origin could be baboon simian T-cell leukemia/lymphoma virus type 1 (STLV-1) or HTLV-1 (before the outbreak started, some Sukhumi baboons were inoculated with human leukemic material). The third possibility entered recently: interspecies transmission of rhesus macaque STLV-1 to baboons. It was prompted by the finding of very close similarity between STLV-1 991-1cc (the strain isolated from a non-Sukhumi baboon inoculated with material from a Sukhumi lymphomatous baboon) and rhesus STLV-1. To test this hypothesis, we investigated 37 Sukhumi STLV-1 isolates from baboons of high-lymphoma stock by PCR discriminating rhesus type and baboon type STLV-1 isolates. All of them were proved to be rhesus type STLV-1. In contrast, all six STLV-1 isolates from baboons belonging to other stocks or populations were of baboon type. The PCR results were fully confirmed by DNA sequence data. The partial env gene gene sequences of all four STLV-1 isolates from Sukhumi lymphomatous baboons were 97 to 100% similar to the sequence of known rhesus STLV-1 and only 85% homologous with the sequence of conventional baboon STLV-1. Thus, interspecies transmission of STLV-1 from rhesus macaques (or closely related species) to baboons occurred at Sukhumi Primate Center. Most probably this event initiated the outbreak of lymphoma in Sukhumi baboons.

Continuous lymphoblastoid suspension cultures from cells of haematopoietic organs of baboons with malignant lymphoma--biological characterization and biological properties of the herpes virus associated with culture cells.

The continuous lymphoblastoid cell lines KMPG-1 and SPG-2 producing baboon herpes virus (HVP) with morphological signs of herpes viruses have been established from haematopoietic organs of lymphomatous baboons. As distinct from H.simplex type I and II viruses HVP is not pathogenic for laboratory rodents. According to its physico-chemical and immunological properties HVP is related to the Epstein-Barr virus.