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Role of Genetic Predisposition in Common Disorders

  • Some traits like intelligence, physical ability and longevity are genetically determined but the effect of external and environmental influences are the main determinants of health and survival
  • With increased control of environment, genetic makeup is becoming more important determinant of individual health
  • Genetic predisposition may lead to the premature onset of common diseases of adult life such as
    • Cancer
    • Coronary heart disease
    • Diabetes
    • Hypertension and
    • Mental disorders
  • Cancer:
    • It is not yet certain if most cancers are hereditary
    • But a genetic predisposition may be involved in 10 – 25% of Ca breast and Ca colon
    • Identification of genes that may affect susceptibility of tumor development, may lead to an improvement in diagnosis and treatment of cancer
    • E.g. a DNA screening test for breast cancer
    • Advice could be offered on the chemoprevention of cancers, tailored for families with different types of cancer risk
  • Coronary Heart Disease (CHD):
    • Until recently only environmental factors alone were believed to cause CHD
    • High blood pressure and high blood cholesterol levels are major risk factors for CHD and both are also genetically influenced
    • A combination of risk detection and lifestyle counselling with drug treatment might cut the incidence of heart attacks to the low levels as two or three generations ago
  • Diabetes:
    • Evidence for a genetic element in insulin dependent DM has emerged from twins studies
    • Higher concordance in identical twins (25 – 30%) than non-identical twins (5 – 10% ) has been reported
    • About 8% of DM in developed countries is of the NIDDM type which has a particularly strong familial tendency
    • Hence diabetes of all types is an important candidate for future treatments with gene therapy of pancreatic tissue transplantation
  • Mental disorders:
    • Family and twin studies have demonstrated the existence of genetic predisposition to some common mental diseases

Alzheimer’s disease

  • Has a strong familial tendency
    • Known to be caused by at least four different genes
  • Knowledge about genetics of common diseases can lead to development of family oriented approach into basic and specialist medical practice
  • A major effort is being made to study the genetic factors involved, develop appropriate therapies and determine how these approaches can best be applied in practice

Reference:

  • Park’s Textbook of Preventive and Social Medicine, 23rd ed.

Eugenics: Eugenics
Negative Eugenics and Positive Eugenics: Eugenics
Euphenics: Euphenics
Euthenics: Euthenics
Genetic Counselling: Genetic Counselling
Neonatal Screening: Neonatal Screening
Prenatal Diagnosis: Prenatal Diagnosis
Gene therapy: Gene therapy
Erythroblastosis Foetalis: Erythroblastosis Foetalis
Role of Genetic Predisposition in Common Disorders: Role of Genetic Predisposition in Common Disorders

Difference between ‘Eugenics’ and ‘Genetic Counselling’: Difference between ‘Eugenics’ and ‘Genetic Counselling’

FAQs in Genetics and Health (lecture): Genetics and Health