• 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: http://www.ihatepsm.com/blog/eugenics
Negative Eugenics and Positive Eugenics: http://www.ihatepsm.com/blog/eugenics
Euphenics: http://www.ihatepsm.com/blog/euphenics
Euthenics: http://www.ihatepsm.com/blog/euthenics
Genetic Counselling: http://www.ihatepsm.com/blog/genetic-counselling
Neonatal Screening: http://www.ihatepsm.com/blog/neonatal-screening
Prenatal Diagnosis: http://www.ihatepsm.com/blog/prenatal-diagnosis
Gene therapy: http://www.ihatepsm.com/blog/gene-therapy
Erythroblastosis Foetalis: http://www.ihatepsm.com/blog/erythroblastosis-foetalis
Role of Genetic Predisposition in Common Disorders: http://www.ihatepsm.com/blog/role-genetic-predisposition-common-disorders
Difference between ‘Eugenics’ and ‘Genetic Counselling’: http://www.ihatepsm.com/blog/difference-between-%E2%80%98eugenics%E2%80%...
FAQs in Genetics and Health (lecture): http://www.ihatepsm.com/category/genetics-and-health