Risk Loci For Chronic Obstructive Disease Reside On Chromosome 14: A Case-Control Study On The Pakistani Population.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD), the third leading cause of death worldwide, is characterized by airflow limitation that can be due to abnormalities in the airway and/or alveoli. Genetic diagnosis at an early stage can be a key factor in the provision of accurate and timely treatment. Single Nucleotide polymorphisms (SNPs) are an important tool to study genetic association/ predisposition of the disease and have great potential to be diagnostic markers for early diagnosis of disease. METHODS: This case-control COPD association study was designed for the five SNPs residing on potential candidate genes (SERPINA1, SERPINA3, RIN3), to check whether these genes are involved in the genetic predisposition for COPD in the Pakistani population or not. The SNAPshot method was used to find out the risk alleles and haplotypes using ABI Genetic analyzer 3130. GeneMapper, Haploview and PLINK 1.9 software were used for analyzing the genotypes and haplotypes taking smoking exposure and gender as covariates. RESULTS: Two of the SNPs, rs4934 and rs17473 were found to be independently and significantly associated with COPD in our studied population whereas haplotype H1 for two SNPs, rs754388 and rs17473 (that are in high linkage disequilibrium), was found to be a significant risk factor for developing COPD symptoms. CONCLUSIONS: SNP variants of SERPINA1 and SERPINA3 are significantly and independently associated with COPD in the local population of Pakistan.

Major histocompatibility complex class II polymorphic variants are associated with asthma predisposition in the Punjabi population of Lahore, Pakistan.

INTRODUCTION: Various genome wide association studies have manifested that Major Histocompatibility Complex (MHC) region on chromosome 6p21 houses many potential candidate genes for asthma. OBJECTIVE: This Case-Control association study was planned to determine the association of 10 Single Nucleotide Polymorphisms (SNPs), residing within and around MHC genes' region on chromosome 6p21, with Asthma in Punjabi population of Lahore, Pakistan. METHODS: A total of 161 subjects, 61 physician-diagnosed asthma patients and 100 age-matched healthy controls, were recruited from Lahore, a city in Punjab. Ten single nucleotide polymorphisms (SNPs) (rs9378249, rs2070600, rs404860, rs6689, rs1049124, rs1063355, rs1049225, rs1049219, rs7773955 and rs928976) located within or near AGER, NOTCH and HLA genes in MHC region, were genotyped in both patients and controls using single base extension reaction and capillary electrophoresis-based genetic analyser. Statistical models were applied using SHEsis Plus. Results were adjusted for various cofactors (age, gender and environment) and by applying multiple corrections. Haplotype and linkage disequilibrium analyses were performed on Haploview software v4.1. RESULTS: Three of the studied SNPs rs1049124, rs1049219 and rs7773955 show independent significant association with asthma under allelic and genotypic models. Two of the haplotypes, H7 and H13, "CTAATTT" and "CCACTAT", respectively, for rs2070600, rs404860, rs6689, rs1049124, rs1063355, rs1049219 and rs7773955, are found to be significantly associated with the disease. CONCLUSION: This study reports association of SNP variants residing on HLA-DQB1 and HLA-DQA2 genes and haplotypes H7 and H13 on genomic region 6p21 with Asthma in the Punjabi population of Lahore, Pakistan.

rs12603332 is associated with male asthma patients specifically in urban areas of Lahore, Pakistan.

OBJECTIVE: rs12603332, an important regulatory site variant, is known to alter the regulatory motif E2A that is involved in the maturation of B-lymphocytes. The study was designed to check whether different environmental exposures alter its risk allele association with asthma or not. METHODS: 200 Physician-diagnosed asthma patients and 108 healthy individuals were enrolled from hospitals of Lahore. After quantitation of DNA extracted from peripheral blood, amplification of genomic region with rs12603332, followed by single base extension (SBE), was performed. Allele and genotype frequencies were calculated by SHEsis and Haploview software packages. Statistical analyses on PLINK were also performed, taking different factors as covariates. HaploReg analysis was done to predict the effect of risk allele on different regulatory motifs. RESULTS: Risk allele for rs12603332 i.e., "C" allele was found to be significantly associated with male patients residing in urban localities. CONCLUSION: The finding suggests that on exposure with urban environment, risk allele carriers tend to develop asthma symptoms via epigenetic regulation of motif associated with maturation of B-lymphocytes.

Autosomal recessive congenital cataract linked to EPHA2 in a consanguineous Pakistani family.

PURPOSE: To investigate the genetic basis of autosomal recessive congenital cataracts in a consanguineous Pakistani family. METHODS: All affected individuals underwent a detailed ophthalmological and clinical examination. Blood samples were collected and genomic DNAs were extracted. A genome-wide scan was performed with polymorphic microsatellite markers. Logarithm of odds (LOD) scores were calculated, and Eph-receptor type-A2 (EPHA2), residing in the critical interval, was sequenced bidirectionally. RESULTS: The clinical and ophthalmological examinations suggested that all affected individuals have nuclear cataracts. Genome-wide linkage analyses localized the critical interval to a 20.78 cM (15.08 Mb) interval on chromosome 1p, with a maximum two-point LOD score of 5.21 at theta=0. Sequencing of EPHA2 residing in the critical interval identified a missense mutation: c.2353G>A, which results in an alanine to threonine substitution (p.A785T). CONCLUSIONS: Here, we report for the first time a missense mutation in EPHA2 associated with autosomal recessive congenital cataracts.

A novel locus for autosomal recessive retinitis pigmentosa in a consanguineous Pakistani family maps to chromosome 2p.

OBJECTIVE: To identify a disease locus for autosomal recessive retinitis pigmentosa in a consanguineous Pakistani family. DESIGN: Prospective linkage study. METHODS: Blood samples were collected and genomic DNA was extracted. A genome-wide scan was performed using 382 polymorphic microsatellite markers on genomic DNA from 4 affected and 5 unaffected family members, and logarithm of odds scores were calculated. RESULTS: A maximum 2-point logarithm of odds score of 3.14 at theta = 0 was obtained for marker D2S165 during the genome-wide scan. Fine mapping markers identified a 20.92-cM (19.98-Mb) interval flanked by D2S149 and D2S367 that cosegregates with the disease phenotype. Haplotype analyses further refined the critical interval, distal to D2S220 in a 12.31-cM (13.35-Mb) region that does not harbor any genes that previously have been associated with retinitis pigmentosa. CONCLUSIONS: Linkage analysis identified a new locus for autosomal recessive retinitis pigmentosa that maps to chromosome 2p22.3-p24.1 in a consanguineous Pakistani family.