Association of CALHM1 gene polymorphism with late onset Alzheimer's disease in Iranian population

Alzheimer's disease [AD] is a genetically heterogeneous neurodegenerative disease and Late-Onset type [LOAD] is the most common form of dementia affecting people over 65 years old. CALHM1 [P86L] encodes a transmembrane glycoprotein that controls cytosolic Ca[2+] concentrations and A beta levels and P86L polymorphism in this gene is significantly associated with LOAD in independent case controls in a number of studies. This study was performed to determine whether this polymorphism contributes to the risk for LOAD in Iranian population. One hundred and forty one AD patients and 141 healthy controls were recruited in this study. After extraction of genomic DNA, the genotype and allele frequencies were determined in case and control subjects using PCR/RFLP method. The statistical analysis showed a significant difference in the heterozygote genotype frequency in case and control groups and polymorphic allele had a protective role between two groups. Also after stratifying the subjects by their APOE-epsilon status, no significant association was observed. Our study suggests that P86L polymorphism could be a protective factor for late-onset Alzheimer's disease [LOAD] in Iranian population. However, to confirm these results, further study with a bigger sample size may be required

New variations in the promoter regions of human DOCK 4 and RAP1A genes, and coding regions of rap1a in sporadic breast tumors

Breast cancer is the most common cancer among women in developed countries. The prevalence of the disease is increasing in the world. Its annual incidence among Iranian women is about 7000 cases. RAP1A, a tumor suppressor gene, is located at 1p13.3 and plays an important role in the cellular adhesion pathway and is involved in the pathogenesis of breast cancer. The DOCK4 gene, which is located at 7q31.1, specifically activates RAPlA gene. In the present study, DNA samples from 64 cases of sporadic breast tumors [referred to Mehrad Hospital in Tehran] were screened using PCR-SSCP method and the number of observed variations compared with the control group [100 normal women]. Mutation detection for coding exons of RAP1A gene and the 500 bp upstream of transcription initiation site as promoters of both DOCK4 and RAPlA were carried out and compared with the control group. The promoter region of DOCK4 showed a heterozygous mutation with G>A transition at nucleotide -303 in a fibroadenoma case. With regard to RAPlA we found a heterozygous mutation, G>A transition in an adenoid cystic carcinoma case, and another heterozygous mutation, G>T transversion in an intraductal papilloma case both at nucleotide +45. A homozygous variation, T>A transversion was also found at nucleotide +29 of a fibroadenoma case. The differences in the frequency of variations mentioned above were not statistically significant. However Fisher's exact showed significant difference for T>A transversion. Although, the higher frequency of these mutations and variations may be related to the disease, a larger sample size is needed for the confirmation of our findings

Lack of association between tumor necrosis factor-alpha -308 C/A polymorphism and risk of developing late-onset alzheimer's disease in an Iranian population

Late-onset Alzheimer's Disease [LOAD] is a neurodegenerative disorder and the most common form of dementia affecting people over 65 years old. Alzheimer's disease is a complex disease with multi-factorial etiology. Inflammation has been approved to have an important role in the pathogenesis of Alzheimer's disease [AD]. TNF-alpha is a main pro-inflammatory cytokine that plays an essential role in initiation and regulation of inflammatory responses. Several studies have shown the probable association of polymorphism at TNF-alpha gene's promoter with AD pathogenesis. This study was performed to determine whether this polymorphism contributes to the risk for late-onset Alzheimer's disease [LOAD] in Iranian population. One hundred and forty AD patients and 158 healthy controls were recruited in the study. Following extraction of genomic DMA, using PCR/RFLP methods the genotype and allele frequencies were determined in case and control subjects. The statistical analysis showed no significant difference in the allele and genotype frequencies due to this polymorphism between the two groups. Also after stratifying the subjects by their APOE-epsilon 4 status, no significant association was observed. Our results suggest that Tumor necrosis factor-alpha [TNF-alpha] -308 C/A is not a risk or protective factor for late-onset Alzheimer's disease in Iranian population. However, to confirm these results further study with a bigger sample size may be required

Genetic heterogencity of PKD1 and PKD2 genes in Iran and determination of the genotype/phenotype correlations is several families with autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease [ADPKD] is the most common genetic nephropathy, which is characterized by replacement of renal parenchyma with multiple cysts. In Iran, the disease prevalence within the chronic hemodialysis patient population is approximately 8-10%. So far, three genetic loci have been identified to be responsible for ADPKD. Little information is available concerning the pattern of linkage in Iranian population. In the present study, the linkage analysis was performed using three pairs of polymorphic microsatellite markers including 16AC2.5-CA [D16S291], SM7-CA [D16S283] and KG8-CA [intragenic marker at the 3' end of the gene]. These markers are closely linked to the ADPKD1 locus and three pairs of the selected polymorphic microsatellite markers including YUNCA9 [D4S231], AFM155xe11 [D4S1534] and AFM224x6 [D4S423], which were closely linked to the ADPKD2 locus. In parallel, the genomic DNA of 150 unrelated healthy individuals was used to determine frequency, heterozygosity rate and polymorphic information content [PIC] for each marker. In our study, haplotypes were constructed in a number of ADPKD families using respective markers. Assignment of the disease gene loci was performed following phasing and haplotype construction, genotype/phenotype correlations were deduced from the constructed haplotypes. Analysis of clinical data confirms a milder ADPKD phenotype for PKD2 families in Iran. Our results showed relatively high heterozygosity rates and PIC values for some markers, while the most informative markers were KG8 [PIC: 0.772] and 16AC2.5 [PIC: 0.689] for PKD1 gene and AFM224x6 [PIC: 0.712] for PKD2 gene. We report here the first molecular genetic study of ADPKD and the existence of locus heterogeneity for ADPKD in Iranian population by performing linkage analysis on 15 affected families. Eleven families showed linkage to PKD1 and two families linked to PKD2 gene. In 2 families, PKD1 markers were common in all affected members but PKD2 markers were not informative

Molecular study of pkd[1]and pkd[2] genes by linkage analysis and determining the genotype/phenotype correlations in several Iranian families with autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease [ADPKD] is an inherited disorder with genetic heterogeneity. Up to three loci are involved in this disease, PKD1 on chromosome 16p 13.3, PKD2 on 4q21, and a third locus of unknown location.Here we report the first molecular genetic study of ADPKD and the existence of locus heterogeneity for ADPKD in the Iranian population by performing linkage analysis on 15 affected families.Eleven families showed linkage to PKD1 and two families showed linkage to PKD2. In two families, PKD1 markers are common in all affected members but PKD2 markers were not informative.The results of this study demonstrate significant locus heterogeneity in autosomal dominant PKD in Iran. Analysis of clinical data confirms a milder ADPKD phenotype for PKD2 families. Our results showed relatively high heterozygosity rates and PIC values for some markers, while the most informative markers were KG8 and 16AC2.5 for PKD1 gene and AFM224x6 for PKD2 gene

Highly sensitive conventional PCR testing of free fetal DNA in maternal serum for non-invasive fetal sex determination

Background: free fetal DNA [FFD] in maternal plasma/serum has increasingly become the source of fetal material for diagnostic purposes in recent years. This source of fetal material can be used for sex determination, Rh typing, paternally inherited sequences and compound heterozygosity. Reports on the lack of consistent PCR amplification of Y-chromosome sequences of FFD in maternal plasma/serum have led diagnostic services to the use of real-time PCR for improved sensitivity of sex determination. We report the use of conventional PCR for fetal sex determination with high sensitivity and reproducibility

Methods: peripheral blood samples were obtained from 21 pregnant volunteers during 4-29 weeks of gestation. A healthy man and 52 healthy non-pregnant women were investigated in this study as controls. All the samples were collected at random. Fetal gender was determined by conventional PCR to detect a Y-chromosomal sequence [DYZ1] in maternal serum and confirmed by amniocentesis or after delivery

Results: fetus-derived Y sequences were detected in 16 out of 17 maternal serum samples with male fetuses and none of the 4 women bearing female fetuses had positive results. The sensitivity of our PCR reached >95%, and the specificity reached >96% [Y signal detected in only 2 out of 52 female samples studied]

Conclusion: our report on the improved sensitivity of Y-chromosome PCR simplifies routine sex determination in diagnostic laboratories without the use of real-time PCR