A preliminary study on the association of single nucleotide polymorphisms of interleukin 4 (IL4), IL13, IL4 receptor alpha (IL4Rα) & Toll-like receptor 4 (TLR4) genes with asthma in Indian adults.

Background & objectives: Interleukin 4 (IL4) and IL13 genes are believed to be responsible for inflammation of the airways in asthmatics. These share a common receptor component called IL4Rα which is another potentially important candidate gene linked to asthma phenotypes. Another gene Toll-like receptor 4 (TLR4) might affect the incidence or progression of asthma through the expression of proinflammatory genes. Several single nucleotide polymorphisms (SNPs) in IL4, IL13, IL4Rα and TLR4 have been reported to be linked to asthma or related phenotypes in several ethnic populations using linkage studies and association studies. However, the results have not been consistent. We investigated five SNPs (C-589T and C-33T of IL4, G+2044A of IL13, A+1902G of IL4Rα, and A+896G of TLR4) in patients with adult onset asthma to evaluate their role in manifestation and severity of asthma. Methods: Adult (>18 yr of age) patients with asthma (n=100) and healthy controls (n=50) were included in the study. Genotyping was performed using sequenom MassARRAY technology. Results: The mutant alleles of the C-589T and C-33T SNPs in the promoter region of IL4 were present in 4 per cent patients with asthma but absent from the control group suggesting that the variations in IL4 may contribute to asthma occurrence. The SNPs of other genes were seen in both controls and patients. Interpretation & conclusions: The results suggest the possible association between the genetic distribution of C-589T and C-33T SNPs of IL4 with asthma in Indian adults.

Insertion-deletions burden in copy number polymorphisms of the Tibetan population.

BACKGROUND: Many studies have been conducted to identify either insertions-deletions (inDels) or copy number variations (CNVs) in humans, but few studies have been conducted to identify both of these forms coexisting in the same region. AIMS AND OBJECTIVES: To map the functionally significant sites within human genes that are likely to influence human traits and diseases. MATERIALS AND METHODS: In this report, we describe an inDel map in the 1051 Tibetan CNV regions obtained through CNV genotyping using Affymetrix Genome-wide single nucleotide polymorphism 6.0 chip. InDel polymorphisms in these copy number polymorphism regions were identified with a computational approach using the 2500 deoxyribonucleic acid sequences obtained from the 1000 Genome Project. RESULTS: The study identified a total of 95935 inDels that range from 1 bp to several bps in length which were found scattered across regulatory regions, exons and in introns of genes underlying the CNVs. A study on the distribution of inDels revealed that the majority of inDels were found in coding regions of the genome than the noncoding, while within the genes, inDels in intron regions were more followed by exonic regions and finally the regulatory regions. CONCLUSION: Study of inDels in CNV regions contribute to the enhanced understanding of the role played by the two variations and their collective influence on the genome. Further, a collection of these inDel genetic markers will aid in genetic mapping, further understanding of the phenotypic variability, identification of disease genes and in detecting novel CNVs.

Association of socio-economic status with family history in adult patients with asthma.

Background & objectives: Socio-economic status is associated with increased morbidity in patients with asthma. The aim of the present study was to assess the association between socio-economic status and family history of asthma in adult asthma patients. Methods: The study included 200 adults with asthma and 400 non-asthmatic controls. Socio-economic status was determined based on income. Regression analysis was used to estimate odd ratios in relation to socio-economic class, using age, gender, family history of asthma and smoking habits. Results: The highest occurrence of having any family history of asthma was observed in the high class group (88.2%), followed by upper middle class (79.5%), lower middle class (60%) and the lowest in the low class group (34%). Having any family history of asthma was an important risk factor in both univariate and multivariate analyses in lower middle class, upper middle class and high class, but not in the low class group. Interpretation and conclusions: The results indicated a positive association between having a family history of asthma and higher socio-economic status. Further studies on a large representative sample need to be conducted to confirm these findings.

An understanding of the genetic basis of asthma.

Asthma is the most common chronic childhood disease in developed nations and its prevalence has increased in the world over the last 25 years. It is a complex disease with both genetic and environmental risk factors. Asthma is caused by multiple interacting genes, some having a protective effect and others contributing to the disease pathogenesis, with each gene having its own tendency to be influenced by the environment. This article reviews the current state of the genetics of asthma in six categories, viz. epidemiology, management, aetiology, family and twin studies, segregation and linkage studies, and candidate genes and single nucleotide polymorphisms (SNPs).

A rare case of congenital heart disease with ambiguous genitalia.

Birth defects have become the important cause of mortality and morbidity in the perinatal period. Congenital heart disease (CHD) is the most common birth defect which includes the varying forms of cardiac abnormalities and occurs with an incidence of 1 per 100 live births. In most of the cases, CHD is an isolated malformation, but about 33% have associated anomalies. Ambiguous genitalia are one such rare anomaly that is associated with CHD among other genital abnormalities. The possible causes for this association could be pseudohermaphroditism, which in turn, may be due to congenital adrenal hyperplasia. The government of any country should consider providing for its people a free prenatal diagnosis for susceptible disorders.

Inheritance patterns, consanguinity & risk for asthma.

Background & objectives: Family history is an important risk factor for the development of asthma, contingent upon genetic and environment interaction. Since there is paucity of data on asthma inheritance in Indian population, the present study was undertaken to investigate the inheritance patterns of asthma and the effect of family history and consanguineous marriage on asthma inheritance. Methods: A total of 200 families, 100 index children and 100 index adults with clinically diagnosed asthma, along with 400 non-asthmatic children and adults as controls were selected for the present study. Information about the family history of each patients and controls was collected and analyzed pedigrees were also constructed. Results: A history of asthma in any member of the family was observed in 44.5 per cent of cases and 5.3 per cent of controls (P < 0.001). A differential risk of developing asthma was noted in family history of asthma in different first and second degree relatives of children and adult patients. Consanguineous marriage was also noted in parents in 24.5 per cent of cases and 12.3 per cent of controls (P< 0.001). The most common mode of asthma inheritance was recessive. Interpretation & conclusions: Our results showed that consanguineous marriage and family history of asthma are important determinants in the development of asthma in the offspring.

Racial divergence of a rare laboratory evolved centromeric fission Cytorace of nasuta-albomicans complex of Drosophila.

Fissioncytorace-1, a member of the nasuta-albomicans complex of Drosophila is an evolutionary product of centric fission, which had occurred in the chromosome X3 of Cytorace 1, a hydridization product of Drosophila nasuta nasuta male (2n=8) and Drosophila nasuta albomicans female (2n=6). Cytorace 1 (males 2n=7; females 2n=6) has inherited this chromosome from its D. n. albomicans parent. The chromosome X3 of D. n. albomicans is a derivative of a centric fusion between the acrocentric chromosome 3 and the chromosome X of D. n. nasuta. The Fissioncytorace-1 has crossed 200 generations from the time of its evolution in the laboratory environment. When this centromeric fission race was subjected to some of the morphophenotypic and fitness assessment to find its overall population fitness showed, increased body size, sternopleural bristle, ovarioles, lifetime fecundity and fertility with reduced interspecific competitive ability and hatching success when compared with its parent (Cytorace 1). These results suggest that the hybrid races must have encountered an early event of recombinational raciation during their evolution in the laboratory environment, which is a unique observation in animal system illustrating the increase in the tempo of evolution after the event of hybridization.

Possible risk factors for Down syndrome and sex chromosomal aneuploidy in Mysore, South India.

BACKGROUND: Down syndrome (DS) and sex chromosomal aneuploidy (SA) are common chromosomal anomalies causing congenital malformations and mental retardation in humans. The well-established risk factor, advanced maternal age, was not found in many of the DS and SA cases in India, while the other possible risk factors have not been well studied. In view of this, the present study has been made. MATERIALS AND METHODS: During the last 5 years, 150 clinically suspected DS and 25 SA cases were referred to our laboratory for chromosome investigation from major hospitals of Mysore city. Chromosome preparations were made from these patients after informed consent was obtained. Well-spread G-banded metaphase plates were analyzed by automated LEICA KARYO software. Two hundred and 100 randomly selected families belonging to different religions were used as controls for the DS and SA cases, respectively. Statistical analysis was carried out using logistic regression RESULTS: Out of the 150 cases of DS, 122 had free trisomy 21, two were mosaic trisomy 21, and one had translocation. Logistic regression of case-control study of DS children revealed that the odds ratio of uncle-niece marriages, or second cousin marriages, or parents lived in rural region, or exposure of the parents to chemicals, or parents education status, or habits (tobacco/ alcohol used) of father, or mother not undergone prenatal scanning, or mothers with previous abortions were significant when all the variables of that category were used one at a time. Exposure of the parents to chemicals, parents’ educational status, habits (tobacco/alcohol use) of the father, mother not undergone prenatal scanning, and history of previous abortions were significant when all the variables of that category were used one at a time. Similarly, except for consanguinity, history of previous abortions, and mother not undergone prenatal scanning, all other factors showed significant odds ratios in SA cases. CONCLUSION: Besides the known risk factors, consanguinity, region (rural/urban) of residence of parents, exposure of parents to chemicals, educational status of parents, habits of father, prenatal scanning, and reproductive performance of mother are possible risk factors for chromosomal aneuploidy.

Self abortion of attacks in patients with Hot Water Epilepsy.

A cross sectional hospital based study was undertaken to find out the various clinical aspects and management of Hot Water Epilepsy (HWE) in children. Of the 71 cases analysed, 67.6% had onset of seizures in the first decade of life. Seizures occurred frequently towards the end of head bath (71.8%). In 14.1% cases, seizures were precipitated with cold-water head bath also. Complex partial seizures (60.6%) and generalized atonic seizures (21.1%) were common. Spontaneous non-reflex epilepsy was seen in 47.9% cases. Self-induction and self-abortion of seizures were seen in 16.9% and 12.7% patients respectively. Family history was available in 32.4% of cases. Majority had good response to continuous prophylactic treatment with antiepileptic drugs. We conclude that high incidence of spontaneous seizures and generalized atonic seizures seem to be peculiar to our geographical area. "Self abortion of attacks"may be of immense help in controlling the attacks.

Missense mutation G296S in GATA4 is not responsible for cardiac septal defects.

BACKGROUND: The most common type of congenital heart disease is the cardiac septal defects, which has reported to be caused by a missense mutation (G296S) in exon 3 of the GATA4 gene. AIMS: The present study was undertaken to find out whether GATA4 gene is the prime cause of the septal defects in Mysore population. MATERIALS AND METHODS: GATA4 gene analyses were undertaken on 21 confirmed CHD cases by PCR and DNA sequencing. RESULTS AND CONCLUSION: Analysis of this particular mutation in 21 septal defect patients revealed that none of the patients had the mutation, indicating that this mutation is population specific or septal defect in Mysore population is caused due to mutations in other regions of the GATA4 gene.

Evolution of phenylthiocarbamide taster trait in Mysore, South India.

BACKGROUND: The ability to taste phenylthiocarbamide (PTC), a bitter chemical has long been known to be a heritable trait, which is being widely used for both genetic and anthropological studies. The frequency of taster and non-taster allele is found to vary in different populations. AIMS AND OBJECTIVE: To investigate the frequency of taster trait in Mysore, South India. MATERIALS AND METHODS: The present investigation was conducted in Mysore, South India during 2002 - 2003. About 3282 subjects irrespective of age, sex, religion, food habits, socio-economic status were randomly selected from various parts of the city and a total of 180 families, which included Christian (50), Hindu (61) and Muslim (69) were screened from different localities of the city. Harris and Kalmus method was used to assess the PTC taster and nontaster phenotype. RESULTS: It was found that tasters were significantly more frequent than nontasters in all the four categories. The incidence of tasters was more in unbiased category (85%) and less in Muslim category (58%). Investigations on PTC tasting in the families of three different religious groups revealed that the tasters were significantly more frequent than nontasters. It was also found that heterozygous father or mother for the taster genes with nontaster partner had taster and nontaster progenies in the ratio 1.0: 1.54 indicating the deviation in the segregation pattern of test cross. CONCLUSION: In Mysore, tasters are more frequent than nontasters. Variation in the frequency of nontaster allele in the religious groups could be due to inbreeding.

Myotonia congenita--a successful response to carbamazepine.

Myotonia congenita is a rare disease of skeletal muscle characterized by painless myotonia, generalized muscular hypertrophy and a non-progressive course. We report a 10-year-old girl with myotonia, "Herculean appearance" and electromyographic confirmation of myotonic discharges. There was a dramatic response to carbamazepine. The aim of this report is to make the readers aware of this entity which can be easily controlled with medication and also prevented by genetic counseling.

An understanding the genetic basis of congenital heart disease.

The recent exponential increase in the knowledge of genetics has revolutionized the understanding of congenital heart diseases (CHDs) during the past few decades. Prior studies have reported the influence of Mendelian disorders on CHDs to be very small, when compared to the polygenic inheritance, which constituted a higher percentage. The recent findings of candidate genes responsible for CHDs have provided new insights into the genetic basis of heart malformation. Here we reviewed the understandings of different types of heart lesions associated with syndromes for which genetic etiologies are apparent, as well as the recent developments involving the molecular pathways involved in CHDs in case of human beings. The similar mutations, which are the devastating events of molecular mechanism, may be the cause of different types of CHDs indicating single gene defects as the cause of different apparent phenotypes. An integrated simple model will explain the causes of presently well known CHDs. This review provides updated information on the genetic basis for cardiac defects which helps to understand, identify, prevent and treat individuals who might be at risk at an early stage. There is a need to find heart defects as early as possible so that they can be treated while the heart is still forming.