Genetic Conditions

What are genes and chromosomes?
A gene is a segment of DNA that is coded to pass along a certain trait; it has a specific task (i.e. determining the color of your eyes). Genes are the simplest building blocks of heredity. They are grouped together in specific patterns within a person's chromosomes, forming the unique "blueprint" for every physical and biological characteristic of that person.

Chromosomes are made up of deoxyribonucleic acid (DNA) molecules. Humans have 46 chromosomes arranged in pairs in every living cell of our bodies. When the egg and sperm join at conception, half of each chromosomal pair is inherited from each parent.

What causes genetic disorders?
Genetic disorders may be caused by of a variety of reasons. Genetic disorders may be caused by abnormalities in the chromosomes, which are referred to as chromosomal abnormalities. Disorders may also be caused by a single gene, which may be identified as dominant, recessive or X-linked disorders.

Dominant Disorders: One gene is defective and it overrides the normal gene Recessive Disorders: Both genes in the pair are defective X-linked Disorders: A defective gene is on an X chromosome, which may be recessive or dominant

The following is a list of potential explanations for birth defects or genetic disorders:

■ Spontaneous mutation

■ Errors in cell division

■ Single gene changes because of environmental exposure to chemicals or radiation

■ Defect in the development of the sperm or the egg

■ Recreational drug use

■ Exposure to lead or industrial chemicals