Children's Genetic Diseases
by Areil Sutton
The cells of the human body are comprised of 23 pairs of chromosomes, one set from the mother and one set from the father. Each chromosome may contain either dominant or recessive genes that determine a person's looks, sex, and predispositions to genetic disorders.
In the case of a dominant disorder, the genetic disorder lies on a dominant gene. When this occurs, only one copy of the gene is required to pass on the disorder. Huntington's disease, Marfan syndrome, and achondroplasia are just a few disorders of this type.
Recessive gene disorders require both parents to have and pass along the recessive gene for the disorder to occur. Sickle cell anemia, phenylketonuria (PKU), cystic fibrosis, and Tay-Sachs disease are widely known recessive disorders.
X-linked disorders only affect the X chromosome. Because of this, women will only be carriers unless both parents carry this gene. Men will have the disorder if the mother carries the gene. Examples of x-linked disorders include hemophilia, Duchenne muscular dystrophy (DMD), and fragile X syndrome.
Chromosomal disorders occur when there is a missing, extra, or damaged chromosome. This error takes place during the formation of either the egg or sperm. Down syndrome, a disorder causing mental retardation and abnormal features, is a widely known chromosomal disorder.
When an abnormality not caused by any one of the above reasons occurs, it is referred to as a multifactorial disorder. Neural tube defects, including spina bifida, and cleft lip/palate are among these disorders.