The dynamics, such as transmission, spatial epidemiology, and clinical course of Coronavirus Disease-2019 (COVID-19) have emerged as the most intriguing features and remain incompletely understood. The genetic landscape of an individual in particular, and a population in general seems to play a pivotal role in shaping the above COVID-19 dynamics. Considering the implications of host genes in the entry and replication of SARS-CoV-2 and in mounting the host immune response, it appears that multiple genes might be crucially involved in the above processes. Herein, we propose three potentially important genetic gateways to COVID-19 infection;these could explain at least in part the discrepancies of its spread, severity, and mortality. The variations within Angiotensin-converting enzyme 2 (ACE2) gene might constitute the first genetic gateway, influencing the spatial transmission dynamics of COVID-19. The Human Leukocyte Antigen locus, a master regulator of immunity against infection seems to be crucial in influencing susceptibility and severity of COVID-19 and can be the second genetic gateway. The genes regulating Toll-like receptor and complement pathways and subsequently cytokine storm induced exaggerated inflammatory pathways seem to underlie the severity of COVID-19, and such genes might represent the third genetic gateway. Host-pathogen interaction is a complex event and some additional genes might also contribute to the dynamics of COVID-19. Overall, these three genetic gateways proposed here might be the critical host determinants governing the risk, severity, and outcome of COVID-19. Genetic variations within these gateways could be key in influencing geographical discrepancies of COVID-19.

The transmembrane P-glycoprotein that functions as a drug-efflux transporter coded by ATP-binding cassette, subfamily B, member 1/Multidrug Resistance 1 (ABCB1/MDR1) gene is considered relevant to drug absorption and elimination, with access to the central nervous system. Effects of three ABCB1 single nucleotide polymorphisms (SNPs) in genotypic and haplotypic combination have been evaluated in a south Indian population for risk of pediatric medically refractory epilepsy. The study included age and sex matched medically refractory (N=113) cases and drug responsive epilepsy patients (N=129) as controls, belonging to the same ethnic population recruited from a tertiary referral centre, of Karnataka, Southern India. The genotype frequencies of SNPs c.1236C>T, c.2677G>T/A, and c.3435C>T were determined from genomic DNA of the cases and controls by PCR- RFLP and confirmatory DNA sequencing. 256 normal population samples of the same ethnicity were genotyped for the three loci to check for population stratification. Results indicate that there was no statistically significant difference between allele and genotype frequencies of refractory and drug responsive epilepsy patients. The predicted haplotype frequencies of the three polymorphisms did not show significant difference between cases and controls. The results confirm earlier observations on absence of association of ABCB1 polymorphisms with medically refractory epilepsy.

DNA methylation has been implicated in the etiopathology of various complex disorders. DNA methyltransferases are involved in maintaining and establishing new methylation patterns. The aim of the present study was to investigate the inherent genetic variations within DNA methyltransferase genes in predisposing to susceptibility to schizophrenia. We screened for polymorphisms in DNA methyltransferases, DNMT1, DNMT3A, DNMT3B and DNMT3L in 330 schizophrenia patients and 302 healthy controls for association with Schizophrenia in south Indian population. These polymorphisms were also tested for subgroup analysis with patient's gender, age of onset and family history. DNMT1 rs2114724 (genotype P = .004, allele P = 0.022) and rs2228611 (genotype P = 0.004, allele P = 0.022) were found to be significantly associated at genotypic and allelic level with Schizophrenia in South Indian population. DNMT3B rs2424932 genotype (P = 0.023) and allele (P = 0.0063) increased the risk of developing schizophrenia in males but not in females. DNMT3B rs1569686 (genotype P = 0.027, allele P = 0.033) was found to be associated with early onset of schizophrenia and also with family history and early onset (genotype P = 0.009). DNMT3L rs2070565 (genotype P = 0.007, allele P = 0.0026) confers an increased risk of developing schizophrenia at an early age in individuals with family history. In-silico prediction indicated functional relevance of these SNPs in regulating the gene. These observations might be crucial in addressing and understanding the genetic control of methylation level differences from ethnic viewpoint. Functional significance of genotype variations within the DNMTs indeed suggest that the genetic nature of methyltransferases should be considered while addressing epigenetic events mediated by methylation in Schizophrenia.

Microbial dysbiosis has been implicated in the pathogenesis of oral cancer. We analyzed the compositional and metabolic profile of the bacteriome in three specific niches in oral cancer patients along with controls using 16SrRNA sequencing (Illumina Miseq) and DADA2 software. We found major differences between patients and control subjects. Bacterial communities associated with the tumor surface and deep paired tumor tissue differed significantly. Tumor surfaces carried elevated abundances of taxa belonging to genera Porphyromonas, Enterobacteriae, Neisseria, Streptococcus and Fusobacteria, whereas Prevotella, Treponema, Sphingomonas, Meiothermus and Mycoplasma genera were significantly more abundant in deep tissue. The most abundant microbial metabolic pathways were those related to fatty-acid biosynthesis, carbon metabolism and amino-acid metabolism on the tumor surface: carbohydrate metabolism and organic polymer degradation were elevated in tumor tissues. The bacteriome of saliva from patients with oral cancer differed significantly from paired tumor tissue in terms of community structure, however remained similar at taxonomic and metabolic levels except for elevated abundances of Streptococcus, Lactobacillus and Bacteroides, and acetoin-biosynthesis, respectively. These shifts to a pro-inflammatory profile are consistent with other studies suggesting oncogenic properties. Importantly, selection of the principal source of microbial DNA is key to ensure reliable, reproducible and comparable results in microbiome studies.

The diatheses of gene and environment interaction in schizophrenia (SCZ) are becoming increasingly evident. Genetic and epigenetic backgrounds are being considered in stratifying and addressing phenotypic variation and drug response in SCZ. But how much of these epigenetic alterations are the primary contributing factor, toward disease pathogenesis and drug response, needs further clarity. Evidence indicates that antipsychotic drugs can also alter the epigenetic homeostasis thereby inducing pharmacoepigenomic effects. We re-examine the context of epigenetics in disease pathogenesis and antipsychotic drug therapy in SCZ to understand how much of these observations act as real indicators of the disease or therapeutic response. We propose that epigenetic viewpoint in SCZ needs to be critically examined under the genetic, epigenetic and pharmacoepigenetic background.