How to Identify Genetic Diseases Through Karyotype

Simply put, a karyotype is a picture of a person's chromosomes. This picture can help researchers and health care professionals determine if a person has or will develop a genetic disease. The information about genetic diseases is stored in our chromosomes. A karyotype with no indication of genetic diseases will have 46 chromosomes, including 22 pairs of autosomes and two sex chromosomes, which determine a person's gender. Any abnormalities in the chromosomes may be an indication of a genetic disease.

Instructions

1. Researchers start the karyotype by first isolating and staining chromosomes and then placing them under a microscope.

2. Through the microscope, a picture is taken. The picture must be cut up, separating the individual chromosomes.

3. The chromosomes are then rearranged according to size from largest to smallest.

4. A medical professional known as a cytogeneticist then examines the rearranged chromosomes and looks for abnormalities, such as too many, too few, missing pieces, or mixed up pieces. For example, a karyotype that has three copies of chromosome 21 has one too many. That person would have the genetic disease known as Down syndrome, or trisomy 21.

References

• University of Utah Genetic Science Learning Center
• The Chromosome 18 Registry & Research Society
• MedicineNet, Inc.