IndexIntroductionMethod: study populationWhole exome sequencingIn silico analysisSanger sequencingResult:Description of the familyBirth history of the family's childrenCommon patient traitsWhole exome sequencingWhole exome sequencing of the probandGene mutation screening GPT2 in the family IntroductionIntellectual disability (ID) is a disease of the central nervous system that affects 2-3% of the world's population. With a wide range of signs and symptoms, three main criteria make up the diagnostic framework of intellectual disability: intelligence quotient (IQ) less than 70, symptoms present before the age of 18, and deficits in at least two adaptive behaviors [Prada 2016; Celis 2015]. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essayThis clinically heterogeneous disorder can develop due to genetic and/or environmental causes. The genetic risk factor, de novo or hereditary, is considered responsible for 25-50% of these cases and this rate increases with the severity of ID [Prada 2016; Kaufman 2010; Celis 2015]. From this perspective, ID can be classified into syndromic and non-syndromic forms. Although more than 450 individual candidate genes for Mendelian ID have been identified, in half of the cases the cause of the disease remains unknown [Kaufman 2010]. The development of DNA sequencing technology over the past decade has marked a dramatic era for the discovery of the genetic etiology of ID. More than thirty studies have been established to provide random variants in various families, including sporadic or familial cases [Rabbani2014]. For example, Najmabadi et al. reported 50 new candidate genes in 136 Iranian families [Najmabadi 2011]. While approximately 1% of the genome (30 Mb) (~3 the genetic pathology of a clinically heterogeneous disorder. Using [WES/Trio WES], we detect a new variant of the GPT2 gene that affects all affected siblings of an Iranian family in the homozygous pattern mutation. Method: study population. The proband was 23 years old. boy from a semi-large Iranian family, who had three sick sisters and three healthy sisters. He suffered from intellectual disability without any malformation. After obtaining the informed consent signed by the parents, a complete clinical evaluation provided by the attending physician together with the registration of the family pedigree by the geneticists of our team. This study has ethical approval from AJA University of Medical Sciences in Tehran, Iran (code:???) Whole exome sequencing Briefly, after blood sample preparation, DNA extraction, enrichment of genomic DNA fragment with >340,000 probes designed against the human genome (Nextera Rapid Capture Exome, Illumina); Library preparation on an Illumina NextSeq or HiSeq 4000 platform (Illumina) was performed with an average depth of coverage of 70-100X. In the Silico analysis, based on the familial inheritance mode, a multistep filtering strategy was applied to restrict the identified variants to a small number. Application of public databases such as 1000 Genome Project, dbSNP, ClinVar, SIFT, Polyphen, Mutation Taster software and internal databases (Iranome) to reach the possible causal variants. Sanger sequencing The candidate variant was confirmed using two-way direct sequencing for all family members (primers and details of PCR reactions are available upon request). Result: Description of the family We report a semi-large family coming from),.