Lecture 5 - Genetics in medicine

Question 1

Genetic disciplines

Answer 1

Medical genetics - explores the genetic contributions to the etiology, pathogenesis, and natural hx of diseases and disorders

Clinical genetics - the diagnosis, prognosis, & treatment of genetic diseases

Question 2

Genetic v. Familial v. Hereditary

Answer 2

Genetic - pathophysiology of the disorder is based on changes in DNA

Hereditary - the DNA change is in the germ cells

Familial - runs in the family (may not always be genetic)(common environment)
Ex. Multiple sclerosis

Question 3

Human Genome

Answer 3

• 3.2 Gb (3.2 billion base pairs)
• aprox. 20k known genes
• 3k genes associated with disease
• Coding region (exons) = 64 Mb (2%)
• 85% of disease causing mutations are in exons

Question 4

Mutation v. Polymorphism

Answer 4

Mutation is any change/deviation from the normal DNA code

Polymorphism is a mutation (variant) that occurs in at least 1% of general population

Question 5

Internet resources for human genetics

Answer 5

ornl.gov
OMIM (ncbi)
GeneReviews (ncbi)
Geneticalliance.org

Question 6

Epidemiology of genetic conditions in clinical medicine

Answer 6

• 60% of pediatric hospital admissions are due to a condition with a genetic basis
• 40% of adult hospital admissions are due to a condition with a genetic basis
• Genetic background has a 30% contribution to a person’s health
• 2-3% of all newborns have recognizable anomaly and additionaln 2-3% ahve unrecognizable anomaly
• 3% of US pop. has intellectual disability
• 5% learning disability in all school age children