Zohreh Nasirian Jazi - Master of molecular cell, biochemistry major, Payam Noor University, Taft branch, Yazd, Iran

What is Down Syndrome? Down syndrome is a condition in which a person has an extra chromosome. Chromosomes are small “packages” of genes in the body. They determine how a baby's body forms and functions as it grows during pregnancy and after birth. Typically, a baby is born with ۴۶ chromosomes. You have probably met people with Down syndrome many times. People who have a special appearance due to having an extra chromosome are mentally different from us and may have some physical limitations. There is no complete cure for this disorder, but people with this disorder can be helped. In this way, there are many rehabilitation and support treatments for them. The combination of these treatments will help them live a more comfortable life. Recent medical advances as well as various supports from society and institutions have made people with Down syndrome better able to face the challenges ahead of them. Down syndrome is a genetic disease that occurs due to the presence of all or part of an extra chromosome in the pair of chromosome ۲۱, which is called trisomy ۲۱ in scientific terms. This disease has various symptoms, including major or minor abnormalities in the structure or function of organs. Down syndrome is a condition in which a baby is born with an extra copy of its ۲۱st chromosome - hence its other name, trisomy ۲۱. This problem delays physical and mental development. Down syndrome (DS) is a genetic disorder appeared due to the presence of trisomy in chromosome ۲۱ in the G-group of the acrocentric region. DS is also known as non-Mendelian inheritance, due to the lack of Mendel’s laws. The disorder in children is identified through clinical symptoms and chromosomal analysis and till now there are no biochemical and molecular analyses. Presently, whole exome sequencing (WES) has largely contributed in identifying the new diseasecausing genes and represented a significant breakthrough in the field of human genetics and this technique uses high throughput sequencing technologies to determine the arrangement of DNA base pairs specifying the protein coding regions of an individual’s genome. Apart from this next generation sequencing and whole genome sequencing also contribute for identifying the disease marker. From this review, the suggestion was to perform the WES is DS children to identify the marker region.

Downs syndrome, Exome sequencing, Chromosomal analysis, Genes, Genetics.