Investigation of mutations in synaptic genes SHANK3 and SHANK2 in autistic spectrum disorders

• Grant number: 13/14919-6
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2013
• End date: February 28, 2015
• Field of knowledge: Health Sciences - Medicine - Psychiatry
• Principal Investigator: Agnes Cristina Fett Conte
• Grantee: Agnes Cristina Fett Conte
• Host Institution: Faculdade de Medicina de São José do Rio Preto (FAMERP). São José do Rio Preto , SP, Brazil
• City of the host institution: São José do Rio Preto
• Associated researchers: Maria Rita dos Santos e Passos Bueno ; Maurício Lacerda Nogueira

Abstract

Autism Spectrum Disorders (ASD) include Autism, Pervasive Developmental Disorder Not Otherwise Specified and Asperger Syndrome, they have in common behavior changes, such as repetitions and stereotypes, communication, like absent speech or poorly developed, and problems with social relationships. Such manifestations are observed before the first three years of life and the severity varies considerably among affected. The prevalence is 1/150, with the ratio of four men for every woman affected. These disorders are complex and heterogeneous etiology unknown in most cases. Only about 10-25% of the cases can be associated with an etiological factor, genetic or environmental, depending of the composition of samples and laboratory techniques used. There are several candidate genes or genomic regions that have mutations and copy number variations (CNVs), which have expression in the central nervous system, many in the synaptic level. Among them are SHANK2 and SHANK3 genes, not yet studied in Brazilian subjects. In SHANK2 on chromossome 11q13.3, mutations have been described in seven of its 25 exons, while in SHANK3, on chromossome 22q13 and with 23 exons, also has descriptions of mutations in several of them, but especially in three. These mutations were observed in autism, but not in controls subjects, suggesting their involvement in the etiology of the disorders. This project aims to evaluate mutations in exons 11, 13 and 22 of the gene SHANK2 and in exons 2, 6 and 22 of SHANK3, that are most frequently involved in the findings in ASD. The study of six exons will be performed by direct sequencing in 200 affected. In case of change detection, the parents will be investigated, and in cases of undescribed mutations, a control group with 200 individuals will be investigated. This study may contribute to clarifying the etiology of these diseases, the understanding of the behavioral phenotype and in Genetic Counseling of families. (AU)