Genetics: Past, Present, and Future

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Genetics Past, Present, and Future

• Robert M. Fineman, M.D., Ph.D.

E-mail Web site
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Genetics is that branch of biology that deals
with heredity and variation.
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Genotype the genetic constitution of an
individual as applied to a single locus or all
the loci collectively when applied to the entire
genetic constitution, it is synonymous with
genome.
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Alleles different forms of a gene at the same
locus on homologous chromosomes.
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Phenotype the appearance or observable nature
of an individual the visible effects of the
interaction of the genotype and the environment.
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Medical Genetics the science or study of
biological variation as it pertains to health and
disease in humans.
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Clinical Genetics or Genetic Medicine (also
known now as Genomic Medicine) that part of
medical genetics concerned with health and
disease in individuals and families.
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Public Health Genetics the use of genetic
information and technology to promote, protect
and, thereby, improve the publics health and
well-being.
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Genetic Screening the use of various methods or
techniques to evaluate populations or groups of
individuals independent of a family history of a
disorder, and without clinical signs or symptoms.
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Genetic Testing the use of various methods or
assays to determine the genetic status of an
individual already suspected to be at high risk
for a particular genetic condition because of a
relevant family history, clinical signs or
symptoms, or a positive screening test result.
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Genetic Variation

• There is no such thing as THE human genome
  sequence.
• There is about a 3 million bp difference between
  any two non-related individuals.
• Common variant sequences (alleles) occur every
  1/1000-1/1500 bp.
• There are an estimated 2-3 common variants per
  gene (on average).

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DNA Mutations

• Nonsense
• Missense
• Frameshift
• Regulatory
• RNA splicing
• Expanding trinucleotide repeats
• Others

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Our Challenge Is One Of Change

• Genetics in the Past
• Human Genome Project/Related Technologies
• New Genetics/Genomics
• Genomic Medicine
• Genomic Medicine and Research
• Genomics and Society

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Medical Genetics Timeline

• 1950s Clinical and mathematical genetics
• 1960s Cytogenetics, biochemical genetics,
  genetic nosology, dysmorphology, NBS
• 1970s Prenatal screening/dx, genetic counseling,
  molecular diagnosis
• 1980s Early genomics, biotechnology

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The Genetics Center Is A Resource For The
Entire Community

• Preconception Care/Data/Education
• Prenatal Care/Data/Education
• Infant/Childhood Care/Data/Education
• Adolescent/Adult Care/Data/Education
• Usually Involves Other Health and Social Services
  Professionals

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Medical Genetics Timeline

• 1990s Computers Internet genetic informatics
  genetics of complex diseases molecular medicine
  ethical, social and legal issues
  commercialization and de-academization
  consumerization

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Genetics in the Past

• Conditions caused by an extra or missing
  chromosome or part of a chromosome
• Conditions caused by a mutation in a single gene
  or in a mitochondria

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Genetics in the Past

• These conditions
• are important to the individuals and
  families who have them
• are relatively rare, even when added together
• do not affect most people
• play a small role in health care and society

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Genetics in the Past

• These conditions are rare enough such that
  genetic services could be provided by genetic
  health care professionals, with occasional
  involvement of primary care professionals and
  other specialists.

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Genetics in the Past

• Regarding research
• because of their relatively small impact on the
  health of our nation, these conditions were of
  limited interest
• only very recently did genetics begin to help
  answer basic health care questions

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Types and Frequencies of Genetic Diseases

• Type
• Chromosomal
• Single Gene
• Multifactorial
• (Emory Rimoin, 1997)

• Lifetime Frequency
• 3.8/1000
• 20/1000
• 646/1000

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Of the ten leading causes of death in the U.S.,
nine are causally related, in part, to
genetic/genomic factors (CDC, 1997).

• Heart Disease (31.0)
• Cancer (23.2)
• Stroke (6.8)
• COPD (4.8)
• Injury (4.2) (? genetic)
• Pneumonia/Influenza (3.9)
• Diabetes (2.8)
• Suicide (1.3)
• Kidney Disease (1.1)
• Chronic Liver Disease (1.1)

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Of the ten leading causes of death worldwide,
nine are causally related, in part, to
genetic/genomic factors
(CDC).

• Heart Disease (13.7)
• Stroke (9.5)
• Pneumonia (6.4)
• HIV/AIDS (4.2)
• COPD (4.2)
• Diarrhea (4.1)
• Perinatal (4.0)
• TB (2.8)
• Tracheal/Bronchial/Lung Cancer (2.3)
• Traffic Accidents (2.2) (? genetic)

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Unfortunately, more than 50 of premature death
and disability in the United States is caused by
things people do to themselves or to others,
e.g., smoking, diet and exercise, alcohol and
drugs, violence, etc.
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The new genetics (or genomics) comes largely
from knowledge derived from the Human Genome
Project and related technologies.