Pedigree

Pedigrees can be used in the clinical setting, such as genetic counseling sessions or genetic evaluations, or in genetic research. By analyzing how many family members have a genetic disorder, how these individuals are related, and the sex of the affected individuals, it is often possible to determine the inheritance pattern of the genetic disorder in the family. Together, the inheritance pattern and an accurate diagnosis help the genetic professional provide accurate risk information to the family. This includes risk information for future pregnancies or relatives who are currently unaffected, but who are at risk for developing the disorder based In this sample pedigree, Sue is the proband, or person first coming to the attention of the geneticist. Birth dates and relevant medical history is also included. on family history information. Genetic testing options, if available, can then be offered to those at risk.

The pedigree is also a standard tool used by researchers. For example, in studies aimed at identifying genes that cause human genetic disorders, researchers must collect detailed information on relatives participating in the study, particularly those relatives who are affected with the disorder. Researchers compare the genes of affected individuals with the genes of those who did not inherit the disorder to identify the specific genes responsible. In other studies the disease-causing gene is known, and researchers study the gene mutation (s). A pedigree can help identify which family members should be included in mutation analysis, as only those family members who are affected or are at-risk could carry a mutation. Researchers can also pictorially show laboratory data, such as genotypes or haplotypes, on the pedigree.