Norm of Mendelian Inheritance in Genetic Disorders
Negative for genetic disorders.
Usage of Mendelian Inheritance in Genetic Disorders
Used prospectively for genetic counseling to predict the probability that future offspring will inherit a genetic disorder; used retrospectively to determine or confirm the presence of a mendelian disease.
Description of Mendelian Inheritance in Genetic Disorders
This procedure is an analysis of gene sequences on a client's DNA and RNA to detect the presence of genetic disorders in the family history or in the client. More than 4000 mendelian diseases obey statistical laws and exist in a family. Examples are breast cancer, colon cancer, color blindness, congenital malformations, cystic fibrosis, hemophilia, Marfan syndrome, and sickle cell anemia. As genetic techniques improve, mendelian testing is becoming more commonly used for population-based screening, such as in screening newborns for phenylketonuria and other disorders. Screening carries with it legal and ethical dilemmas concerning confidentiality, privacy, discrimination, and interventions taken based on findings.
Professional Considerations of Mendelian Inheritance in Genetic Disorders
Consent form NOT required.
- Provide teaching.
- A family pedigree analysis is performed, including generational continuity of the disorder, sex relationship, and segregation (mendelian) ratio.
- Genetic counseling and referral for follow-up study.
Client and Family Teaching
- Inform the client about the reasons for genetic counseling.
Factors That Affect Results
- Gene-mapping is most accurate in identifying simple genetic disorders, such as those caused by a single abnormal gene. Newer techniques are being developed to help identify genetic causes of more complicated diseases.
- Other disorders can mimic mendelian disorders, such as chromosomal disorders, congenital infections, and mental retardation.
- The Online Mendelian Inheritance in Man (OMIM) databases, available via the worldwide web, provide up-to-date information on gene mutation findings.