Rare variants in obsessive-compulsive disorder

Author(s)

Carolina Cappi

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2013-08-07

Examining board members

Euripedes Constantino Miguel Filho; Ronaldo Fumio Hashimoto; Guilherme Vanoni Polanczyk; David Schlesinger

• Advisor: Euripedes Constantino Miguel Filho

Abstract

Studies of rare variations have been used successfully to characterize regions of the genome and molecular pathways conferring risk for developmental neuropsychiatric disorders. Within this context, whole-exome sequencing for rare single-nucleotide variation (SNV) and de novo mutation (DNM) mutation has become an essential approach for gene discovery in psychiatric disease. To date, few if any studies of SNVs and de novo variation using this technology have been reported for obsessive-compulsive disorder (OCD). In the present study, all coding regions of the genome were sequenced for 20 sporadic probands with OCD and their parents, to investigate de novo and inherited rare variations in probands. Subsequently, based on the observation that the products of genes associated with similar diseases are likely to interact with each other heavily in a network of proteinprotein interactions (PPIs), a PPI network was generated, with the genes (protein) with non-synonymous de novo variation, to observe the most important genes in the network. To investigate the relevance of this network to OCD further, degree-aware disease gene prioritization (DADA) was applied, to rank all genes with non-synonymous de novo variation based on their relatedness to a set of genes previously identified in an OCD genetics meta-analysis. In addition, pathway analyses using de novo and inherited variation were completed. Altogether, 10 non-synonymous de novo variations (9 missense, 1 nonsense) were successfully validated by Sanger sequencing. We found that the genes WWP1, AP1G1 and CR1, from the initial non-synonymous de novo variation gene list, were highly interconnected in the PPI. The WWP1 gene had the highest rank in the DADA analyses. Results of the pathway analyses suggest the enrichment of genes involved in immunological systems. In short, almost all genes involved in the DNMs of the present study are expressed in the human brain and implicated in synaptogenesis and neuronal apoptosis (AU)

• FAPESP's process: 08/11537-7 - Copy number variation in the genome of patient with obsessive compulsive disorder
• Grantee: Carolina Cappi
• Support Opportunities: Scholarships in Brazil - Doctorate