TY - JOUR T1 - Exome sequencing in families with severe mental illness identifies novel and rare variants in genes implicated in Mendelian neuropsychiatric syndromes. JF - Psychiatry Clin Neurosci Y1 - 2019 A1 - Ganesh, Suhas A1 - Ahmed P, Husayn A1 - Nadella, Ravi K A1 - More, Ravi P A1 - Seshadri, Manasa A1 - Viswanath, Biju A1 - Rao, Mahendra A1 - Jain, Sanjeev A1 - Mukherjee, Odity KW - Bipolar Disorder KW - Exome KW - Female KW - Genetic Predisposition to Disease KW - Genetic Variation KW - Genome-Wide Association Study KW - Humans KW - Male KW - Pedigree KW - Phenotype KW - Schizophrenia AB -

AIM: Severe mental illnesses (SMI), such as bipolar disorder and schizophrenia, are highly heritable, and have a complex pattern of inheritance. Genome-wide association studies detect a part of the heritability, which can be attributed to common genetic variation. Examination of rare variants with next-generation sequencing may add to the understanding of the genetic architecture of SMI.

METHODS: We analyzed 32 ill subjects from eight multiplex families and 33 healthy individuals using whole-exome sequencing. Prioritized variants were selected by a three-step filtering process, which included: deleteriousness by five in silico algorithms; sharing within families by affected individuals; rarity in South Asian sample estimated using the Exome Aggregation Consortium data; and complete absence of these variants in control individuals from the same gene pool.

RESULTS: We identified 42 rare, non-synonymous deleterious variants (~5 per pedigree) in this study. None of the variants were shared across families, indicating a 'private' mutational profile. Twenty (47.6%) of the variant harboring genes were previously reported to contribute to the risk of diverse neuropsychiatric syndromes, nine (21.4%) of which were of Mendelian inheritance. These included genes carrying novel deleterious variants, such as the GRM1 gene implicated in spinocerebellar ataxia 44 and the NIPBL gene implicated in Cornelia de Lange syndrome.

CONCLUSION: Next-generation sequencing approaches in family-based studies are useful to identify novel and rare variants in genes for complex disorders like SMI. The findings of the study suggest a potential phenotypic burden of rare variants in Mendelian disease genes, indicating pleiotropic effects in the etiology of SMI.

VL - 73 IS - 1 ER - TY - JOUR T1 - Mutation burden profile in familial Alzheimer's disease cases from India. JF - Neurobiol Aging Y1 - 2018 A1 - Syama, Adhikarla A1 - Sen, Somdatta A1 - Kota, Lakshmi Narayanan A1 - Viswanath, Biju A1 - Purushottam, Meera A1 - Varghese, Mathew A1 - Jain, Sanjeev A1 - Panicker, Mitradas M A1 - Mukherjee, Odity KW - Aged KW - Alzheimer Disease KW - Amyloid beta-Protein Precursor KW - Genetic Association Studies KW - Genetic Predisposition to Disease KW - Genetic Variation KW - Humans KW - India KW - LDL-Receptor Related Proteins KW - Membrane Transport Proteins KW - Middle Aged KW - Mutation KW - Presenilin-1 KW - Risk KW - Signal Transduction KW - Tissue Plasminogen Activator KW - Whole Exome Sequencing AB -

This study attempts to identify coding risk variants in genes previously implicated in Alzheimer's disease (AD) pathways, through whole-exome sequencing of subjects (N = 17) with AD, with a positive family history of dementia (familial AD). We attempted to evaluate the mutation burden in genes encoding amyloid precursor protein metabolism and previously linked to risk of dementias. Novel variants were identified in genes involved in amyloid precursor protein metabolism such as PSEN1 (chr 14:73653575, W161C, tgg > tgT), PLAT (chr 8:42039530,G272R), and SORL1 (chr11:121414373,G601D). The mutation burden assessment of dementia-related genes for all 17 cases revealed 45 variants, which were either shared across subjects, or were present in just the 1 patient. The study shows that the clinical characteristics, and genetic correlates, obtained in this sample are broadly comparable to the other studies that have investigated familial forms of AD. Our study identifies rare deleterious genetic variations, in the coding region of genes involved in amyloid signaling, and other dementia-associated pathways.

VL - 64 ER -