Human genetic disorder is mainly caused by different kind of gene known as variation or modification of gene known as mutation. There are many diseases which are associated with the aspects of genes. Some like cancer are caused by gene mutation. Mutation can occur randomly or due to exposure to the environment like smoke from cigarette. Some of genetic disorders are inherited. Mutated genes are passed down from one generation to another through a family and each child can inherit those genes which causes the disorder. Other genetic disorders are because of problems with different number of packages of genes known as chromosomes like Down syndrome. Human genetic disorders are the main cause of death, disability and human tragedy. It is rare to find in a family which is entirely free from any kind of genetic disorder. Genetic defects are mainly known to cause pregnancy loss in developed countries and several spontaneous miscarriages involve fetus with abnormal chromosomes (McKusick, 15).