This document discusses human genetics and health. It notes that genetic disorders and non-communicable diseases have become a major cause of morbidity and mortality as environmentally related disorders have decreased. An individual's health is based on both uncontrollable genetic factors and controllable factors like diet and lifestyle. The document then provides information on genetics, prevalence of genetic disorders, types of genetic disorders, diseases with genetic predisposition, and the role of genetics in predisposing individuals to conditions. It discusses prevention, screening, counseling, gene therapy, eugenics, and genetic services.

1. Human Genetics & Health
Dr Mohan Lal
Associate Professor
Department of Community Medicine
Govt. Medical College, Amritsar

2.  Over the last Few decades, a significant
transition has taken place in the etiology of
diseases affecting mankind
 Environmentally related disorders have
decreased &genetic disorders & non-communicable
disorders have become a
major cause of morbidity and mortality

3. Health of an individual is based on
 Uncontrollable Factors (genetics, gender,
predisposition to a disease)
 Controllable Factors (diet, smoking status,
exercise levels)

4. Genetics
 Study of inheritance dealing with the
transmission of hereditary characters from one
generation to another.
 Human genetics is concerned with the
inheritance of human traits & their relationship to
the human health
 Deals with the herediatry disorders & provide
key to their prevention &control .

5. Prevalence of Genetic Disorders
 Prevalence of genetic disorders (excluding
multifactoral genetic disease)-7/1000 live
births.
 Out of 7,
-4 sex linked disorders
-2 Autosomal disorders
- other characterized by balanced or
unbalanced chromosomal rearrangements
Genetic Liability in the community .

6. Genetic Disorders
Autosomal Dominant Autosomal Recessive Sex Linked disorders
Retinoblastoma Albinism Hemophilia
Marfan Syndrome Total color blindness Agammaglobunemia
Neurofibromatosis Phenylketouria Red green color
blindness
Fibrocystic disease of
Pancreas
Neonatal Jaundice

7. Diseases Associated with Genetic
Predisposition
 Cancer
 Coronary heart disease
 Diabetes (Insulin dependent)
 Alzheimer’s disease

8. Biological Determinant Genetics
Predisposition to disease
 A person may be at increased risk of inheriting a disease or
condition if they have a biological parent who has had the disease.”
 Genetics can have an influence on a persons risk to certain
conditions or diseases.
 Ex: If your parent has high cholesterol, you are at a higher risk of
developing high cholesterol.
 Examples of diseases – genetic predisposition Alzheimer's disease
(before the age of 65)
 Migraine headaches
 Type 1 & 2 diabetes
 CVD - High blood pressure, hypertension
 Certain cancers – (including breast and prostate)

9. Prevention & Control of Genetic
Disorders
1. Prevention
2. Screening
3. Counseling

10. Prevention
Primary Prevention
(Prevent birth of an
affected newborn)
Secondary Prevention
To Prevent clinical
manifestations
in affected individuals
by appropriate
intervention
Tertiary Prevention
Provision of
adequate care &
rehabilitation in
affected individuals

11. Specific Protection
 From X-Ray
 Early diagnosis by :-
-Detection of carriers
- Prenatal diagnostics
- Amniocentesis
-New born screening
- Pre clinical case recognition

12. Screening
 Applied at Prenatal, Neonatal& general
population levels.
 Prenatal & neonatal screening –ideal
approach for early diagnosis & prompt
treatment of herediatry disorders

13. Prenatal Screening
 Prenatal screening by:-
-Ultrasonography fetal malformation &
fetal growth abnormalities
 -Amniocentesis(14-16 weeks of
pregnancy ) diagnosis of spina bifida & other neural
tube abnormalities.
 Chorionic villus sampling technique (10-12 weeks
of pregnancy) – Both biochemical & structural
abnormalities can be detected.

14. Neonatal Screening
 Help in detecting herediatry disorders like
-Phenylketouria
-Sickle cell Anemia
-Duchene muscular dystrophy

15. Population Screening
 To identify individuals at risk of developing herediatry
disorders.
 Objective:-
- To make presymptomatic diagnosis for
arresting the progress of such disease by timely
preventive intervention.
-Only such disorders should be Identified for
which measures for prevention & treatment are
available.

16. Genetic Counseling
 Genetic counseling -an integral part of the management of patients and
families with genetic disorders .
-Retrospective Counseling :- Parents who have already given
birth to a child affected with genetic condition
-Prospective Counseling:-with those at high risk for genetic
disorders & screens them to find out if they really are affected.

17. Genetic Counseling
A educational process by which patients or/& at
risk individuals are given information to
understand the nature of the genetic disease, its
transmission and the options open to them in
management and family planning

18. Essential Components of Counseling
 History of family background construction
 Clinical diagnosis
 Confirmatory diagnosis
 Calculation of reoccurrence of risk
 Counseling
 Follow up

19. Genetic counseling Process
 Beneficiaries :- Individual or couple
Why?
•Have affected child
•Are carriers
•Have genetic disease in family
•Have recurrent abortions
•High maternal/paternal age
•Exposed to a mutagen/teratogenic
•Are consanguineous

20. Reaching accurate diagnosis
 Family history
 Physical/clinical examination
 Cytogenetic studies/radiology
 Laboratory/DNA analysis

21.  Estimation of Recurrence Risk :-
 Family pedigree
 Applying various
methods
 Risk calculation
 -Bayesian
 -Mendels

22.  Genetic Counseling :-
 Available options
 Risk calculations
 New developments
 Disease course
 Treatment availability

23.  Decision Making:-
 Knowledge of disease
recurrence
 Available options
 ·Family pressure
 ·Religious beliefs
 ·Social status
 ·Economic status
 ·Community influence

24. Gene Therapy
 Means introduction of gene sequence in to cell with
the aim of modifying the cell behavior in a clinically
relevant fashion.
Used in many ways :- -
 To correct genetic mutation (as for cystic fibrosis)
 To kill a cell (as for cancer)
 To modify susceptibility (as coronary heart disease )
The gene may be introduced using a virus or by
means of a lipid or receptor targeting .

25. Eugenics
 Idea of herediatry improvement by selective breeding
propagated by Galton.
 Can be defined as improvement of human species or
race by selective breeding .
 Positive Eugenics:-
 Applied to animals for increasing milk & have better
quality animals.
 Improving yield of grains
 Genetic manipulation for human welfare & survival
 Negative Eugenics example “purify” German race by
eliminating genetically poor individuals.

26. Euthenics
 Means providing appropriate / suitable environments for genotype to
express themselves fully.
 Euthenics measures must be comprehensive to include
physical,intellectual,social & cultural components whereby genetically
disadvantaged individuals can achieve a reasonable degree of
development
 Measures to improve the environment in order to improve health,
appearance, behavior, or well-being of society.
 Lead an independent existence.

27. Genetic Services
 Medical termination of Pregnancy 1971 lays down
legislative framework of application of genetics science
 PC-PNDT act 1974-
 Sex Selective abortions need to be eliminated by
implementation of PC-PNDT Act.
 Antenatal clinics provide opportunity to educate
individual & family on genetics.
 Screening of Antenatal mothers for Rh grouping
 Avoidance of teratogenic drugs & radiation
 Promoting immunization against rubella before
pregnancy is preventive genetics.

28.  Contraception for limiting the size of family &
bearing children at right age is a example of positive
& preventive genetics.
 Improving nutritional status & consuption of Iron &
folic acid
 Use of ultrasonography to detect defective children
is essentially a good screening activity.
 Early childhood development services in ICDS
programme by providing environmental stimuli is an
attempt to realize full potential of genetic
endowment of young children.

29. Thank You