Publications by authors named "Ambalavanan A"

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  • The study hypothesizes that better cardiorespiratory fitness (CRF) can slow down aging, especially in people with chronic airflow limitation (CAL).
  • Researchers analyzed DNA methylation and conducted exercise tests on 78 participants aged 40 and older to see how CRF impacts biological aging.
  • Findings showed that higher initial CRF was linked to slower aging according to various epigenetic markers, suggesting that improving CRF could benefit health in those with chronic respiratory issues.
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  • The study investigates the impact of the human milk microbiota (HMM) on the long-term health of children, particularly focusing on asthma and allergic conditions like atopy.
  • Researchers followed 885 mothers and their children from birth to age 5, linking HMM composition to the mothers' genetics and children's health outcomes.
  • Findings suggest that certain bacterial communities in human milk, especially decreased diversity and increased Lawsonella, are correlated with higher rates of childhood atopy and asthma, highlighting the genetic influence on HMM composition.
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  • This study explores the relationship between maternal genetics, human milk oligosaccharides (HMOs), and respiratory health in infants fed human milk.
  • Researchers quantified 19 HMOs from 980 mothers and identified genetic markers linked to HMOs on several chromosomes, including notable findings on chromosomes 19 and 3.
  • The study suggests that certain HMOs may help reduce the risk of respiratory issues, like recurrent wheezing, in preschoolers, depending on their genetic predispositions.
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  • Dysanapsis is the mismatch between airway size and lung size that can lead to COPD risk; it first appears early in life.
  • Researchers analyzed genetic factors linked to dysanapsis through a genome-wide association study involving over 11,000 adults.
  • They found specific genetic variants and developed a genetic risk score that correlated with obstructive lung function in both children and adults, suggesting dysanapsis may connect genetic factors to lung health issues across a person's life.
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The investigation is the first report on genome-wide identification and characterization of NBLRR genes in pearl millet. We have shown the role of gene loss and purifying selection in the divergence of NBLRRs in Poaceae lineage and candidate CaNBLRR genes for resistance to Magnaporthe grisea infection. Plants have evolved multiple integral mechanisms to counteract the pathogens' infection, among which plant immunity through NBLRR (nucleotide-binding site, leucine-rich repeat) genes is at the forefront.

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Background: Evidence suggests that prenatal air pollution exposure alters DNA methylation (DNAm), which could go on to affect long-term health. It remains unclear whether DNAm alterations present at birth persist through early life. Identifying persistent DNAm changes would provide greater insight into the molecular mechanisms contributing to the association of prenatal air pollution exposure with atopic diseases.

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Background: Wheezing in early life is associated with asthma in adulthood; however, the determinants of wheezing trajectories and their associations with asthma and lung function in childhood remain poorly understood.

Objective: In the CHILD Cohort Study, we aimed to identify wheezing trajectories and examine the associations between these trajectories, risk factors, and clinical outcomes at age 5 years.

Methods: Wheeze data were collected at 8 time points from 3 months to 5 years of age.

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Background: Finding specific scientific articles in a large collection is an important natural language processing challenge in the biomedical domain. Systematic reviews and interactive article search are the type of downstream applications that benefit from addressing this problem. The task often involves screening articles for a combination of selection criteria.

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Article Synopsis
  • The study focuses on the genetic background of the Nunavik Inuit, revealing that they have a unique genetic profile that is distinct from both contemporary Europeans and Native Americans.
  • It finds that the Nunavik Inuit population has experienced a small effective population size of 3,000 and a historical split from Greenlandic Inuit around 10,500 years ago.
  • The research identifies specific genomic adaptations in Nunavik Inuit related to fatty acid metabolism and links an exonic variant to a significantly increased risk of intracranial aneurysms (IAs).
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  • SMPD1 gene variants, particularly p.L302P and p.fsP330, are associated with an increased risk of developing Parkinson's disease (PD) in certain populations, specifically the Ashkenazi Jewish cohort.
  • Analysis revealed that lower acid-sphingomyelinase activity in PD patients is linked to an earlier onset of the disease, indicating its potential role as a biomarker.
  • Experimental findings showed that SMPD1 mutations disrupt the normal function of acid-sphingomyelinase, leading to higher levels of α-synuclein in dopaminergic cells, which may contribute to the pathogenesis of PD.
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Childhood-onset schizophrenia (COS) is a rare and severe form of schizophrenia, defined as having an onset before the age of 13. The male COS cases have a slightly younger age of onset than female cases. They also present with a higher rate of comorbid developmental disorders.

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Essential Tremor is a prevalent neurological disorder of unknown etiology. Studies suggest that genetic factors contribute to this pathology. To date, no causative mutations in a gene have been reproducibly reported.

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Childhood-onset schizophrenia (COS) is a rare and severe form of schizophrenia defined as onset before age of 13. Here we report on two unrelated cases diagnosed with both COS and alternating hemiplegia of childhood (AHC), and for whom two distinct pathogenic de novo variants were identified in the ATP1A3 gene. ATP1A3 encodes the α-subunit of a neuron-specific ATP-dependent transmembrane sodium-potassium pump.

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Background: MAPT haplotypes are associated with PD, but their association with rapid eye movement sleep behavior disorder is unclear.

Objective: To study the role of MAPT variants in rapid eye movement sleep behavior disorder.

Methods: Two cohorts were included: (A) PD (n = 600), rapid eye movement sleep behavior disorder (n = 613) patients, and controls (n = 981); (B) dementia with Lewy bodies patients with rapid eye movement sleep behavior disorder (n = 271) and controls (n = 950).

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Alzheimer's disease (AD) is the most common neurodegenerative disorders in the elderly. To identify rare genetic factors other than apolipoprotein E ɛ4 allele (ApoE ɛ4) contributing to the pathogenesis of late-onset AD (LOAD), we conducted a whole-exome analysis of 246 ApoE ɛ4-negative LOAD cases and 172 matched controls in Hong Kong Chinese population. LOAD patients showed a significantly higher burden of rare loss-of-function variants in genes related to immune function than healthy controls.

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  • Intracranial Aneurysm (IA) is prevalent worldwide, affecting 1-3% of the population, with a notably higher incidence in the French-Canadian population due to a founder effect and a familial pattern of occurrence.
  • The study genotyped a cohort of 257 familial IA patients alongside 1,992 controls, identifying a significant locus at 3p14.2 (FHIT) linked to IA, confirmed through further testing in Inuit families and additional cohorts.
  • Two new potential IA loci were identified in the French-Canadian population: FHIT, related to hypertensive IA, and CCDC80, suggesting genetic relevance to IA development, alongside the confirmation of an existing locus at 18q11
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Bipolar disorder (BD) is a prevalent mood disorder that tends to cluster in families. Despite high heritability estimates, few genetic susceptibility factors have been identified over decades of genetic research. One possible interpretation for the shortcomings of previous studies to detect causative genes is that BD is caused by highly penetrant rare variants in many genes.

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Objective: To assess the contribution of variants in , , and as essential tremor (ET) predisposing factors following their association in a 2-stage genome-wide association study (GWAS).

Methods: The coding regions of these genes was examined for the presence of rare variants using two approaches: (1) Looking at whole-exome and whole-genome sequencing data of 14 autosomal dominant multiplex ET families. (2) Conducting a targeted massive parallel sequencing to examine the three genes in cohorts of 269 ET cases and 287 control individuals.

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Introduction: Mutations in teneurin transmembrane protein 4 were reported to be a risk factor for essential tremor, but the relevance of this across different population remains to be examined. The aim of this study was to determine the frequency and spectrum of variations in teneurin transmembrane protein 4 in a cohort of Canadian essential tremor cases.

Methods: The coding portion of teneurin transmembrane protein 4 was sequenced in 269 unrelated essential tremor cases and 288 matched control individuals using a targeted and high-throughput sequencing approach.

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Intracranial aneurysms (IAs) are the result of focal weakness in the artery wall and have a complex genetic makeup. To date, genome-wide association and sequencing studies have had limited success in identifying IA risk factors. Distinct populations, such as the French-Canadian (FC) population, have increased IA prevalence.

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De novo mutations (DNM) are an important source of rare variants and are increasingly being linked to the development of many diseases. Recently, the paternal age effect has been the focus of a number of studies that attempt to explain the observation that increasing paternal age increases the risk for a number of diseases. Using disease-free familial quartets we show that there is a strong positive correlation between paternal age and germline DNM in healthy subjects.

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The lysosomal enzyme glucocerebrosidase (GCase), encoded by GBA, has an important role in Parkinson disease (PD). GBA mutation carriers have an increased risk for PD, earlier age at onset, faster progression, and various nonmotor symptoms including cognitive decline, REM sleep behavior disorder, hyposmia, and autonomic dysfunction.(1) Furthermore, GCase enzymatic activity is reduced in the peripheral blood(2) and brain(3) of noncarrier, sporadic PD patients.

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Background: The protein NgR1 is encoded by RTN4R, a gene linked to schizophrenia. We previously reported NgR1 as receptor for the epilepsy-linked protein LGI1. NgR1 regulates synapse number and synaptic plasticity, whereas LGI1 antagonizes NgR1 signaling and promotes synapse formation.

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