Genetic variants have been reported to cause several genetic diseases. Various genotyping assays have been developed for diagnostic and screening purposes but with certain limitations in sensitivity, specificity, cost effectiveness and/or time savings. Since the discovery of ligase chain reaction (LCR) in the late nineties, it became one of the most favored platforms for detecting these variants and also for genotyping low abundant contaminants. Recent and powerful modifications with the integration of various detection strategies such as electrochemical and magnetic biosensors, nanoparticles (NPs), quantum dots, quartz crystal and leaky surface acoustic surface biosensors, DNAzyme, rolling circle amplification (RCA), strand displacement amplification (SDA), surface enhanced raman scattering (SERS), chemiluminescence and fluorescence resonance energy transfer have been introduced to both LCR and ligation based amplifications to enable high-throughput and inexpensive multiplex genotyping with improved robustness, simplicity, sensitivity and specificity. In this article, classical and up to date modifications in LCR and ligation based amplifications are critically evaluated and compared with emphasis on points of strength and weakness, sensitivity, cost, running time, equipment needed, applications and multiplexing potential. Versatile genotyping applications such as genetic diseases detection, bacterial and viral pathogens detection are also detailed. Ligation based gold NPs biosensor, ligation based RCA and ligation mediated SDA assays enhanced detection limit tremendously with a discrimination power approaching 1.5aM, 2aM and 0.1fM respectively. MLPA (multiplexed ligation dependent probe amplification) and SNPlex assays have been commercialized for multiplex detection of at least 48 SNPs at a time. MOL-PCR (multiplex oligonucleotide ligation) has high-throughput capability with multiplex detection of 50 SNPs/well in a 96 well plate. Ligase detection reaction (LDR) is one of the most widely used LCR versions that have been successfully integrated with several detection strategies with improved sensitivity down to 0.4fM.

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Down-expressed genes associated with DNA hypermethylation could be used as biomarkers for understanding complex pathogenic mechanisms underlying presbycusis.

Introduction: Presbycusis, an age-related hearing impairment (ARHI) disease, is the most common cause for HI in adults worldwide. One of the best candidate genes for ARHI susceptibility is Cadherin 23 (CDH23) which encodes stereocilia tip-links of the inner ear sensory hair cell. Although alterations in the methylation status of CpG dinucleotides across various genes were reported to be associated with HI, methylation changes in CDH23 gene have not been reported previously.Objectives: This study aimed at investigating whether DNA methylation level of CDH23 gene at intragenic CpG island overlapping an exonic-intronic region at position chr10:73565570-73565827 (GRCh37/hg19) could be risk factor associated with ARHI.Materials and Methods: We screened for methylation changes in this particular position for CDH23 gene in 50 blood samples of elderly women affected with presbycusis and healthy control cohort. Methylation of CpG sites were assessed using Quantitative methylation-specific PCR (qMSP) following sodium bisulfite DNA conversion chemistry. Methylation levels were normalized against TSH2B reference gene.Results: DNA methylation analysis for the common CpG islands in CDH23 gene revealed 3.27-folds significant increase (p < 0.0001) in methylation profile for ARHI women as compared to healthy controls with an elevated risk odds ratio (OR) of 2.219 [95% CI 1.071–4.597].Conclusion: Our study is the first of its kind to prove that higher CpG site methylation levels in CDH23 gene are likely to be associated with ARHI.

Fumonisin B (FB) and aflatoxin B (AFB) are fungal metabolites that frequently co-occur in foodstuffs and are responsible for mycotoxicosis and several primary cancers. Cinnamon essential oil (CEO) has a spacious range of benefit effects but also has some limitations owing to its strong taste or its interaction with some drugs. This study aimed to use the cinnamon oil emulsion droplets (COED) for the protection against oxidative stress, cytotoxicity, and reproductive toxicity in male Sprague-Dawley rats sub-chronically exposed to FB and/or AFB. The composition of CEO was identified using GC-MS then was encapsulated using whey protein as wall material. Male rats were divided into eight groups and treated orally for 8 weeks as follows: control group, AFB-trreated group (80 μg/kg b.w), FB-treated group (100 mg/kg b.w), FB plus AFB-treated group, and the groups treated with COED plus FB and/or AFB. Blood and samples of the kidney, liver, and testis were collected for different analysis and histopathological examination. The GC-MS analysis revealed that cinnamaldehyde, α-copaene, trans-cinnamaldehyde, caryophyllene, and delta-cadinene were the main compounds in COE. The average size of COED was 235 ± 1.4 nm and the zeta potential was - 6.24 ± 0.56. Treatment with FB and/or AFB induced significant disturbances in the serum biochemical analysis, oxidative stress parameters, DNA fragmentation, gene expression, and testosterone and severe pathological changes in the tested organs. Moreover, treatment with both mycotoxins induced synergistic toxic effects. COED did not induce toxic effects and could normalize the majority of the tested parameters and improve the histological picture in rats treated with FB and/or AFB. It could be concluded that COED induce potential protective effects against the single or combined exposure to FB and AFB.