@article {120171, title = {Sample size requirement for achieving multisite harmonization using structural brain MRI features.}, journal = {Neuroimage}, year = {2022}, month = {2022 Nov 23}, pages = {119768}, abstract = {

When data is pooled across multiple sites, the extracted features are confounded by site effects. Harmonization methods attempt to correct these site effects while preserving the biological variability within the features. However, little is known about the sample size requirement for effectively learning the harmonization parameters and their relationship with the increasing number of sites. In this study, we performed experiments to find the minimum sample size required to achieve multisite harmonization (using neuroHarmonize) using volumetric and surface features by leveraging the concept of learning curves. Our first two experiments show that site-effects are effectively removed in a univariate and multivariate manner; however, it is essential to regress the effect of covariates from the harmonized data additionally. Our following two experiments with actual and simulated data showed that the minimum sample size required for achieving harmonization grows with the increasing average Mahalanobis distances between the sites and their reference distribution. We conclude by positing a general framework to understand the site effects using the Mahalanobis distance. Further, we provide insights on the various factors in a cross-validation design to achieve optimal inter-site harmonization.

}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2022.119768}, author = {Parekh, Pravesh and Bhalerao, Gaurav Vivek and John, John P and Venkatasubramanian, G} } @article {78111, title = {Adverse childhood experiences in families with multiple members diagnosed to have psychiatric illnesses.}, journal = {Aust N Z J Psychiatry}, year = {2020}, month = {2020 Jun 15}, pages = {4867420931157}, abstract = {

OBJECTIVE: Adverse childhood experiences are linked to the development of a number of psychiatric illnesses in adulthood. Our study examined the pattern of adverse childhood experiences and their relation to the age of onset of major psychiatric conditions in individuals from families that had ⩾2 first-degree relatives with major psychiatric conditions (multiplex families), identified as part of an ongoing longitudinal study.

METHODS: Our sample consisted of 509 individuals from 215 families. Of these, 268 were affected, i.e., diagnosed with bipolar disorder ( = 61), obsessive-compulsive disorder ( = 58), schizophrenia ( = 52), substance dependence ( = 59) or co-occurring diagnoses ( = 38), while 241 were at-risk first-degree relatives who were either unaffected ( = 210) or had other depressive or anxiety disorders ( = 31). All individuals were evaluated using the Adverse Childhood Experiences - International Questionnaire and total adverse childhood experiences exposure and severity scores were calculated.

RESULTS: It was seen that affected males, as a group, had the greatest adverse childhood experiences exposure and severity scores in our sample. A Cox mixed effects model fit by gender revealed that a higher total adverse childhood experiences severity score was associated with significantly increased risk for an earlier age of onset of psychiatric diagnoses in males. A similar model that evaluated the interaction of diagnosis revealed an earlier age of onset in obsessive-compulsive disorder and substance dependence, but not in schizophrenia and bipolar disorder.

CONCLUSION: Our study indicates that adverse childhood experiences were associated with an earlier onset of major psychiatric conditions in men and individuals diagnosed with obsessive-compulsive disorder and substance dependence. Ongoing longitudinal assessments in first-degree relatives from these families are expected to identify mechanisms underlying this relationship.

}, issn = {1440-1614}, doi = {10.1177/0004867420931157}, author = {Someshwar, Amala and Holla, Bharath and Pansari Agarwal, Preeti and Thomas, Anza and Jose, Anand and Joseph, Boban and Raju, Birudu and Karle, Hariprasad and Muthukumaran, M and Kodancha, Prabhath G and Kumar, Pramod and Reddy, Preethi V and Kumar Nadella, Ravi and Naik, Sanjay T and Mitra, Sayantanava and Mallappagiri, Sreenivasulu and Sreeraj, Vanteemar S and Balachander, Srinivas and Ganesh, Suhas and Murthy, Pratima and Benegal, Vivek and Reddy, Janardhan Yc and Jain, Sanjeev and Mahadevan, Jayant and Viswanath, Biju} } @article {45299, title = {Exome sequencing in families with severe mental illness identifies novel and rare variants in genes implicated in Mendelian neuropsychiatric syndromes.}, journal = {Psychiatry Clin Neurosci}, volume = {73}, year = {2019}, month = {2018 Oct 27}, pages = {11-19}, abstract = {

AIM: Severe Mental Illnesses, 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 genetic architecture of SMIs.

METHODS: We analyzed 32 ill subjects from 8 multiplex families; and 33 healthy individuals by whole exome sequencing. Prioritized variants were selected by a 3-step filtering process, which included deleteriousness by 5 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 a 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 {\textquoteright}private{\textquoteright} mutational profile. Twenty (47.6\%) of the variant harboring genes were previously reported to contribute to the risk of diverse neuropsychiatric syndromes; 9 (21.4\%) of which were of Mendelian inheritance. These included genes carrying novel deleterious variants such as GRM1 gene implicated in Spinocerebellar ataxia 44 and NIPBL gene implicated in Cornelia de Lange syndrome.

CONCLUSION: NGS 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. This article is protected by copyright. All rights reserved.

}, issn = {1440-1819}, doi = {10.1111/pcn.12788}, author = {Ganesh, Suhas and Ahmed P, Husayn and Nadella, Ravi Kumar and More, Ravi Prabhakar and Sheshadri, Manasa and Viswanath, Biju and Rao, Mahendra and Jain, Sanjeev and Mukherjee, Odity} } @article {51000, title = {INDEX-db: The Indian Exome Reference Database (Phase I).}, journal = {J Comput Biol}, year = {2019}, month = {2019 Jan 07}, abstract = {

Deep sequencing-based genetic mapping has greatly enhanced the ability to catalog variants with plausible disease association. Confirming how these identified variants contribute to specific disease conditions, across human populations, poses the next challenge. Differential selection pressure may impact the frequency of genetic variations, and thus detection of association with disease conditions, across populations. To understand genotype to phenotype correlations, it thus becomes important to first understand the spectrum of genetic variation within a population by creating a reference map. In this study, we report the development of phase I of a new database of genetic variations called INDian EXome database (INDEX-db), from the Indian population, with an aim to establish a centralized database of integrated information. This could be useful for researchers involved in studying disease mechanisms at clinical, genetic, and cellular levels.

}, issn = {1557-8666}, doi = {10.1089/cmb.2018.0199}, author = {Ahmed P, Husayn and V, Vidhya and More, Ravi Prabhakar and Viswanath, Biju and Jain, Sanjeev and Rao, Mahendra S and Mukherjee, Odity} }