GENETIC TESTS
Types of Genetic Tests
a) Karyotype
b) Fluorescence in situ hybridization
c) Gene testing
d) Biochemical testing
GENETIC TESTS
b) FLUORESCENCE IN SITU HYBRIDIZATION (FISH)
- Analysis of details of chromosomal abnormalities
- Using fluorescence to visualize a targeted region of a chromosome
GENETIC TESTS
CYSTIC FIBROSIS
- Discovery of the gene: 1989, Hospital for Sick Children in Toronto, Lab of Lap-Chee Tsui
- Gene on chromosome 7, mutation of CFTR gene (over 1600 different mutations)
- Genetic test: 85-90% effective
- Affects 1/3600 Canadian children; Carrier 1/25 Canadians
GENETIC TESTS
HUNTINGTON DISEASE
- Gene Huntingtin; first human disease mapped to a chromosome
- Gene on chromosome 4, determined by CAG repeats (greater than 35 is affected)
GENETIC COUNSELLING
GENETIC COUNSELLOR: health care professional specializing in medical genetics and counseling
- Often uses a pedigree to discuss probabilities
- Can also counsel on genetic disorders that are not inherited
GENETIC COUNSELLING
GENE THERAPY: treating genetic disorders by introducing the correct form of the defective gene into a patient’s genome
- Obstacles: type of vector, poor integration of gene into
chromosomes, results are short lived
GENETIC COUNSELLING
GENE THERAPY
1. Normal gene is inserted into a vector (usually DNA of a virus but some elicit immune responses)
2. Vector enters human cells and delivers normal gene
3. Correct protein is made from the new gene