lymphotoxin-alpha gene polymorphism and asthma in Egyptian children

Tumor necrosis factor is a proinflammatory cytokine found in increased concentrations in asthmatic airways. The TNF-alpha [TNFA] and lymphotoxin-alpha [LTA] genes belong to the TNF gene superfamily located within the human major histocompatibility complex on chromosome 6p in a region repeatedly linked to asthma. In this study, we examined 30 asthmatic of average age +/- SD of 8.3 +/- 3.6 y and 28 non-asthmatic Egyptian children. We used the PCR-RFLP analysis to identify the polymorphism +252A>G in intron 1 in lymphotoxin-alpha gene. The frequency of the family history was more common [60%] than isolated asthmatic ones. Asthma was significantly more common in subjects with allele A of the LTA*Ncol polymorphism [55%], rather than allele G [45%]. The LTA*Ncol-A/A genotype [40%] was the preferable genotype to LTA*Ncol-G/A and LTA*Ncol-G/G genotypes. In addition, the severe persistent asthmatic cases were associated with the LTA*Ncol-AA genotype at a frequency of 80%, while the genotype LTA*Ncol-GG are associated with the mildest form of the disease. However, someone could predict the severity of asthma and hence the polymorphism of the LTA*Ncol. More than 93% asthmatic population lived in the randomized areas of Cairo where the air pollution. In conclusion, genotype frequencies for the LTA+252 polymorphisms were significantly different from controls. These findings may have implications for future early intervention studies by helping to identify infants at increased risk for wheezing and childhood asthma

Updated listing of mutation map at the human phenylalanine locus among Egyptian population

Phenylketonuria is the most common inborn error of amino acid metabolism in Egypt with a relatively higher incidence of 1:7.500. Unrelated fifty-one PKU probands were selected from the database-records at the Medical Genetics Center, AinShams University-Cairo. We analyzed the DNA samples using polymerase chain reaction [PCR] combined with restriction enzyme assays, or allele specific oligonucleotide [ASO] testing and direct sequencing to detect 10 PAH gene mutations in exons 2, 3, 6, 7 and 11. We interestingly identified a novel missense CpG site R243P mutation. Moreover, three new known mutations L48S, delEX3 and Y277D unreeled in the Egyptian population. The ten detected mutations covered 58% representing 47 positive chromosomes. The most common mutation was represented by IVS10nt546 [10.8%], while the total missense mutations in our sample group account for the majority of mutations 40%. The high heterozygosity of the mutant PAH locus in Egypt suggests that multiple founder events would explain the presence of hyperphenylalaninemia in Egypt. Further studies will however be necessary to fully exploit the potential of PAH gene analysis to reconstruct the genetic history of PKU in Egypt in context with migrations among European and Mediterranean populations

Association between polymorphisms within tumor necrosis factor genes and the development of bronchial asthma among Egyptian children

Tumor necrosis factor [TNF] is a proinflammatory cytokine that is eminently important in the pathogenesis of bronchial asthma. Bronchial asthma is a frequent respiratory disease characterized by variable airflow obstruction, inflammation of the airways, and bronchial hyper-responsiveness [BHR]. In an effort to find out the polymorphism[s] in genes whose variant[s] have been implicated in asthma phenotypes, we examined the genetic effects of TNF [TNFA and TNFB] polymorphisms on the Egyptian asthmatic children. In this study, skin prick test [SPT], total IgE level, pulmonary functions including FVC, PEF, FEV[1] and FEF[25-75], and bronchial asthma hyper-responsiveness [BHR], were investigated. Sixty asthmatic subjects, as defined by standard MRC respiratory questionnaire, plus 40 healthy controls were genotyped for two common single-nucleotide polymorphisms [SNP] using enzymatic digestion of polymerase chain reaction [PCR]. Asthma was significantly more common in subjects with TNFA-1031C>T [P= 0.007]. Although the SNP containing TNFB+252A>G polymorphism might seem to be excluded in our sample as a cause of the disease [P= 0.6], it was in a very strong linkage disequilibrium with TNFA-1031C>T [P= 0.000002]. All the TNFA-1031C>T genotypes were in a strong association with the severity of the asthma. Incidentally, the LT alpha Ncol-AA [80%] was the most predominant genotype with the severe form. However, someone might predict the severity of asthma and consequently the phenotype of an asthmatic individual by knowing the polymorphism of either the TNFA-1031C>T or even the LT alpha Ncol. These findings may have implications for future early intervention studies by helping to identify infants at increased risk for childhood asthma

Gene analysis and carrier detection of Duchenne muscle dystrophy in Egyptian families

Duchenne and Becker muscular dystrophy [D/BMD] are X-linked recessive disorders resulting from mutations in the DMD gene. Since there is no cure or effective treatment for progressive muscular dystrophy, prevention of the disease is important and strongly depends on carrier status in-formation. Two-thirds of DMD/BMD cases are familial, thus female relatives are candidates for carrier-risk assessment. Segregation analysis of polymorphic short tandem [CA]n repeats [STR-[CA]n] was used to establish and compare the haplotypes of DMD patients with those of their at-risk relatives in order to determine the carrier status. However, 59 D/BMD index families and 35 of their at-risk female relatives were analyzed using the ion-pair reversed phase high performance liquid chromatography [IP-RP-HPLC] method. Comparison between the results of CPK of the carriers and linkage analysis revealed that values higher than the normal level were compatible in 100% of the cases with the carrier status. On the other hand, normal values do not distinguish between the healthy and carrier populations. In conclusion, the unlabeled IP-RP-HPLC-STR assay represents an excellent molecular tool for carrier-status identification and consequently the genetic counseling for the early prevention of such diseases

Polymorphisms of TAP1/LMP7 loci in Egyptian patients with vitiligo

Vitiligo is a very common, often heritable acquired disorder characterized by well-circumscribed milky white cutaneous macules devoid of identifiable melanocytes. Vitiligo appears to be more commonly observed in parts of the body exposed to the sun and in darker skin types and may develop at any age. Our study contained 47 unrelated Egyptian young-aged vitiligo patients [age range 2-18 y] and 14 healthy volunteers of matched age range. All patients experienced active vitiligo lesions with no signs of other autoimmune disorders. To genotype the TAP1 [C>T intron 7] and LMP7 [G>T intron 6], we amplified the genomic DMA using polymerase chain reaction [PCR] using genomic DNA followed by enzymatic digestion. Our results showed no significant difference between TAP1 C>T [intron 7] and LMP7 G>T [intron 6] alleles and healthy controls [p= 0.3 or 0.5, respectively]. Even so, the odd ratios [ORs] for the genotypes of the TAP1 [C>T] were 1.78 [0.4 to 7.0], 0.8 [0.5 to 1.2], and 1.19 [0.2 to 4.9] for the TAP1-CC, CT, TT-genotypes, respectively. The ORs of LMP7 [intron G>T] genotypes were 1.4 [0.3 to 6.0], 0.8 [0.5 to 1.3], 1.19 [0.3 to 3.6] for GG, GT, and TT, respectively. However, a major contribution of both TAP1 and LMP7 polymorphisms to vitiligo susceptibility cannot be excluded. Further studies of other alleles within the TAP and LMP gene regions in Egyptian patients is recommended to demonstrate a possible role for MHC class I antigen processing and/or presentation pathway in the antimelanocyte autoimmune response in vitiligo pathogenesis

Comprehensive rapid identification of female carriers of DMD/BMD by ion-pair reversed-phase high performance liquid chromatography

The unlabeled ion-pair reversed-phase high performance liquid chromatography [IP-RP-HPLC] was used in this study to develop a simple and rapid method for rapid identification of female carriers of the dystrophin gene. DNA molecular size markers were efficiently used to type the 2-bp short tandem repeat [STR]. In an Egyptian sample of 98 chromosomes, the most common alleles within the DMD gene were 200, 176, 245 and 243 bp due to STR44, 45, 49, and 50 markers, respectively. The true heterozygosity values of these markers ranged from 73.5 to 90.9% and observed allele numbers ranged from 8 to 17 in 98 chromosomes, revealing high polymorphism of the four [CA]n system of the DMD gene

Glutathione S-transferase Ml genotype [GSTM1] plus prenatal exposure to smoke as risk factors for pediatric asthma

Pediatric asthma is considered a complex multifactorial disease, with an obvious genetic predisposition and the possible involvement of noxious environmental factors. Glutathione S-transferase genes are known as risk factors predisposing to some environmentally induced diseases. This study has examined the hypothesis that glutathione S-transferase [GSTM1] genotype may play a role in asthma and wheezing occurrence among those exposed to tobacco smoke. Genomic DNA samples isolated from 35 asthmatic children and 35 healthy children were amplified using the flanking GSTM1 primer set premixed with the internal set. Asthmatic children showed a significant high prevalence of the GSTM1-null genotype [odds ratio [OR] 2.2, 95% confidence interval [Cl] 1.4-3.4]. Among GSTM1-null children, in utero smoke exposure was associated with increased prevalence of asthma [OR 3.7, 95% Cl 1.9-7.3]. The intermediate electrophilic metabolites, arising in the first phase of detoxification of tobacco smoke, are not utilized by GST enzyme in asthmatic children. These intermediate metabolites may therefore attack cells and provoke oxidative stress, which contribute to the pathogenesis of asthma. Our findings indicate that there are important long-term effects of in utero smoke exposure in a genetically susceptible group of children [genetic environmental interaction]