Estimation of Risks of Genetic Counselling
POLYGENIC DEFECTS - MULTIFACTORIAL INHERITANCE
Naming of the common disease like Diabetes and hypertension have some genetic basis, however other factors like the environment also is responsible.
Transmitance / Development of disorder depends on both genetic as well as environmental factors ; not genetic alone.
- Increased risk is greatest among closest relatives and decreases rapidly with distance relationship.
- Risk of recurrence with depend upon incidence of the disorders unlike mendelians inheritance.
- Close relations and high heritability of disorders – increases the risk.
- More severely affected proband rarely with disease.
- Multiple family members can be affected.