Improved microsatellite instability detection in colorectal cancer patients by a combination of fourteen markers especially DNMT3a, DCD, and MT1X.

BACKGROUND: Microsatellite instability (MSI) results from genetic and epigenetic changes. Studying Microsatellite instability can help in treatment and categorization of colorectal cancer (CRC) patients. OBJECTIVES: We aimed to investigate whether 14 genomic markers consisting of BAT-62, BAT-60, BAT-59a, BAT-56a, BAT-56b, DCD, RIOX, RNF, FOXP, ACVR, CASP2, HSP110, MT1X, and DNMT3a can increase the detection rate of MSI in CRC. METHODS: Samples were stratified by pentaplex panel (Promega) and 14 markers using multiplex PCR and fragment analysis. In MSI+ samples, to identify the pattern of BRAF V600E mutation and MLH1 promoter methylation, ARMS-scorpion, and Methylation-Specific High-Resolution Melting Curve analysis, were applied respectively. RESULTS: Totally, 35 MSI+ cases identified by 14 marker panel. Only 18 cases of them were detected by both panels which are pentaplex and 14 marker. On the other hand, 17 new MSI+ cases just were identified by 14 markers panel. The highest diagnostic value among 14 markers is related to three makers, namely DCD, MT1X, and DNMT3a. In MSI+ cases, the rate of MLH1 promoter methylation was insignificant, (P value = 0.3979) while the rate of observed BRAFV600E mutation was significantly higher (P value = 0.0002). CONCLUSION: Fourteen marker panel showed higher sensitivity in comparison with the pentaplex panel increasing the detection rate of MSI+ cases up to 1.94 fold. Three markers namely DNMT3a, DCD, and MT1X of 14 marker panel were the best among them showing excellent diagnostic value. A combination of these markers showed 100% sensitivity and specificity in the studied group. In contrary to the markers in the pentaplex panel, these markers had the ability to detect MSI without any bias for the clinicopathological features. These markers will help to identify more end-stage MSI+ tumors which are located distal colon.

Ellis-van Creveld syndrome: Report of a case and recurrent variant.

BACKGROUND: Ellis-van Creveld syndrome (EvCS) is a rare autosomal recessive skeletal dysplasia that is characterized by short stature, short limbs, short ribs, polydactyly and structural heart defect. Despite locus heterogeneity, in the majority of the cases, the disorder segregates with mutations in the EVC and EVC2 genes, notably mutations with truncating protein as a final sequence. In the present study, we report the prenatal findings and genetic analysis of a terminated pregnancy affected by severe thoracic and skeletal dysplasia. METHODS: After detailed physical and clinical examination, whole exome sequencing (WES) was performed and the variant was confirmed by Sanger sequencing. RESULTS: One homozygote variant in EVC2 gene was identified in the fetus (NM_147127, c.942G>A, p.W314X). The EVC2 gene is strongly associated with EvCS, which is consistent with the sonographic findings of the fetus. CONCLUSIONS: The homozygous p.W314X mutation found in this family was recently reported to be segregated in a consanguineous family originating from Pakistan. The occurrence of the p.W314X mutation in two unrelated families (Iranian and Pakistani) may be the result of an old founder effect or arose because of a mutational hotspot and is supporting evidence for the pathogenicity of this variant. Because skeletal dysplasia belongs to a broad spectrum of syndromes and therefore exhibits considerable background locus and allelic heterogeneity, our report highlights the need for appropriate genetic counseling and supports the feasibility of WES to determine an accurate diagnosis, as well as precise recurrence risk prediction.

Triploidy and Routine Combined First Trimester Pregnancy Screening.

BACKGROUND: This report is about a pregnancy with a triploid fetus and underscores the potential of first trimester combined screening to detect this devastating chromosomal aberration earlier in pregnancy. This report is about a pregnancy with a triploid fetus identified from the first trimester combined screening and confirmed by amniocentesis. METHODS: A 28 year old, G5P2AB2 woman was referred to our clinic at 15 weeks of gestation due to a remarkable decrease of her first trimester double biochemical markers and therefore in the high-risk range for trisomy 13 and 18. The woman underwent amniocentesis which revealed a karyotype of 69,XXX. The parents opted for termination and in post mortem physical examination, a hydrocephalus fetus with marked Intra-Uterine Growth Retardation (IUGR) in addition to syndactyly of third and fourth digits, low set malformed ears, micrognathia and club foot, was seen. RESULTS: Our results and previous reports highlight the need to consider a somewhat consistent pattern of the first trimester combined screening in a pregnancy with triploidy and underscore the potential of this screening strategy to detect this chromosomal aberration earlier in pregnancy. CONCLUSION: Early prenatal diagnosis of this syndrome would provide women an opportunity to terminate an affected pregnancy earlier. This is also important in preventing the risks of associated later induced abortion or obstetric complications.

RAB7L1 promoter polymorphism and risk of Parkinson's disease; a case-control study.

INTRODUCTION: Recent genome-wide association studies have explored some new loci in association with Parkinson's disease (PD). RAB7L1 is an important gene involved in one of the important neurological pathways, located in PARK16 locus. We performed a case-control study to examine the association between rs823144 SNP located in the promoter region of the RAB7L1 gene and PD risk in Iranian population. METHODS: A total of 960 samples including 480 PD patients and 480 healthy controls were collected for analysis of the RAB7L1 rs823144 polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR - RFLP) method. RESULTS: We found significant differences in genotypic and allelic frequencies between patients and controls. Significant association was found between presence of minor allele (C) and decreased risk of PD development (p = 0.008, OR = 0.74 (0.605-0.924)). Also another significant association was observed between the CC genotype and PD (p = 0.004, OR = 0.441 (0.252-0.772)). CONCLUSION: Our data support the association between rs823144 and decreased risk of PD.

RIT2 Polymorphisms: Is There a Differential Association?

Neurological disorders include a wide variety of mostly multifactorial diseases related to the development, survival, and function of the neuron cells. Single-nucleotide polymorphisms (SNPs) have been extensively studied in neurological disorders, and in a number of instances have been reproducibly linked to disease as risk factors. The RIT2 gene has been recently shown to be associated with a number of neurological disorders, such as Parkinson's disease (PD) and autism. In the study reported here, we investigated the association of the rs12456492 and rs16976358 SNPs of the RIT2 gene with PD, essential tremor (ET), autism, schizophrenia (SCZ), and bipolar disorder (BPD; total of 2290 patients), and 1000 controls, by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Significant association was observed between rs12456492 and two disorders, PD and ET, whereas rs16976358 was found to be associated with autism, SCZ, and BPD. Our findings are indicative of differential association between the RIT2 SNPs and different neurological disorders.

Single nucleotide polymorphisms of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) in Iranian patients with TB.

BACKGROUND: Two important genes for controlling TB are IFNγ and IFNγR1. However, little information exists regarding genetic susceptibility of the Iranian TB population. METHODS: We investigated the single nucleotide polymorphisms (SNPs) in genes of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) and serum level of IFNγ and their influence on TB in patients; 300 patients with TB and 300 healthy controls were enrolled in this study. PCR-restriction fragment length polymorphism was used to identify SNPs and serum level of IFNγ was measured by ELISA. RESULTS: The allelic and the genotypic form of IFNγ+874 A/T SNP of the studied population were not significant (p>0.05). Allele T frequencies of IFNγR1 -56 C/T promoter region in patients with pulmonary TB (PTB) or extrapulmonary TB (EPTB) were significantly greater than allele C. The -56 TT motif of IFNγR1 is associated with both forms of TB (p<0.05). The serum level of IFNγ was significantly higher in patients with TB than in controls, but there was no significant difference between serum level of IFNγ and the studied genotypes (p>0.05). CONCLUSIONS: The cause of active TB in the patients seems to be due to the lack of effective IFNγ function or the lack of effective signaling connection between IFNγ and its receptor in presence of -56 C/T polymorphism in promoter region of IFNγR1 gene.

The rs1572931 polymorphism of the RAB7L1 gene promoter is associated with reduced risk of Parkinson's disease.

INTRODUCTION: Parkinson's disease (PD) is one of the most common neurologic disorders affecting about 2% of people over 65 years old and both genetic and environmental factors are involved in its aetiology. The genetic part includes several genes and polymorphisms that are the direct cause of disease or its susceptibility factor. The rs1572931 polymorphism of RAB7L1 gene, located in the promoter region, has been recently studied and shown to be strongly associated with reducing risk of PD. In this study, we aim to investigate its association with PD in Iranian population. METHODS: We examined the association of rs1572931 polymorphism with PD in 490 unrelated Patients and 490 normal controls by PCR-RFLP method in Iranian subjects. RESULTS: A significant difference in genotype and allele frequencies was observed between patients and controls (p value = 0.003, OR (95% CI) = 0.71(0.56-0.90)). The TT genotype and the T allele were both significantly less frequent in PD cases. CONCLUSION: Our results confirmed the protective effect of the rs1572931 SNP on PD and replicated the results of previous studies, in Iranian subjects. We suggest further studies in other populations.

Detection of copy number changes in genes associated with Parkinson's disease in Iranian patients.

Parkinson's disease (PD) is the second most common neurodegenerative disorder, after Alzheimer's disease. Genomic rearrangements are common mutations reported in PD patients. In this study, we investigated the prevalence of genomic rearrangements in a total of 232 Iranian PD patients, out of which 102 were sporadic early-onset (age-at-onset ≤ 45 years) and 51 had a family history. We used multiplex ligation-dependent probe amplification (MLPA) method to detect exon dosage changes. Two new improved probe kits, SALSA P051 and P052, were used and altogether α-synuclein, parkin, UCHL1, PINK1, DJ-1, LRRK2, GCH1, ATP13A2, CAV1, CAV2, LPA and TNFRSF9 genes were analyzed. Exon or whole-gene rearrangements were identified in 14 (13.7%) sporadic early-onset PD patients in parkin, α-synuclein and PINK1. Of familial PD patients 46 cases from 18 families (35.3%) showed exon or whole-gene rearrangements in parkin, α-synuclein, PINK1, DJ-1, and ATP13A2 genes. All changes were verified by quantitative PCR (qPCR). Novel mutations and unusual clinical features are reported in this study. Mutations in parkin were the predominant genetic cause in both early-onset and familial PD groups. Also the mutations observed in family PD group are more in number and diversity than the sporadic early-onset PD group.

Biased homozygous haplotypes across the human caveolin 1 upstream purine complex in Parkinson's disease.

The alpha-synuclein-caveolin 1 axis is suggested to be of role in the pathogenesis of Parkinson's disease in cell line models. The objective of this study was to analyze the homozygous haplotype compartment of the human caveolin 1 gene upstream purine complex in patients afflicted with Parkinson's disease. This complex was screened in patients with Parkinson's disease (n = 141) and compared with a group of controls (n = 760) using polymerase chain reaction and sequencing. The expression activity of the homozygous haplotypes was then examined using luciferase Dual-Glo system in human neuronal cell line, LAN-5. Six haplotypes were found to be homozygous in the patients, and not in the control pool (Fisher exact p < 1 × 10(-6)). Three of those haplotypes were specific to Parkinson's disease (Fisher exact p < 0.002), and the remaining three overlapped with homozygous haplotypes in Alzheimer's disease and multiple sclerosis (Fisher exact p < 0.002). The disease haplotypes contained motif lengths that were nonexistent in the control homozygous haplotype pool and significantly increased gene expression (p < 9 × 10(-6)). We conclude that skew in the caveolin 1 purine complex homozygous haplotype compartment and an additive effect of those haplotypes may be linked with Parkinson's disease.