Conclusion
Human genetic disorder occurs due to abnormalities of individuals of genetic materials. Human genetic disorders are of different types depending on the causes. There are four types of genetic disorders; single-gene, chromosomal, multifactorial and mitochondrial. Genetic disorders are mainly caused by mutation of genes and DNA. Each type of disorder has different cause. For example chromosomal disorder is caused by mutation of chromosomes. Swap of DNA by chromosomes to form variety of the gene pool can result to disorder leading to exchange of regions. Through abnormalities of genes and chromosomes human genetic disorder occurs. Some disease like cancer is as a result of genetic disorder but they can occur because of environmental factors. Most human genetic disorders are rare and they affect one person in a million. Some recessive gene disorders give advantage to the heterozygous states in some environments.