1. Genetic screening
© 2016 Paul Billiet ODWS

2. Uses Carrier screening Screening pre-implantation embryos
Prenatal diagnostic screening
Newborn screening
Pre-symptomatic screening in adults
Confirming diagnosis
© 2016 Paul Billiet ODWS

3. Tests
Over 1000 tests available Alzheimer's disease* (APOE; late-onset variety of senile dementia) Inherited breast and ovarian cancer* (BRCA 1 and 2; early-onset tumors of breasts and ovaries) Hereditary nonpolyposis colon cancer* (CA; early-onset tumors of colon and sometimes other organs) Cystic fibrosis (CF; disease of lung and pancreas resulting in thick mucous accumulations and chronic infections) Hemophilia A and B (HEMA and HEMB; bleeding disorders) Huntington's disease (HD; usually midlife onset; progressive, lethal, degenerative neurological disease) Phenylketonuria (PKU; progressive mental retardation due to missing enzyme; correctable by diet) Sickle cell disease (SS; blood cell disorder; chronic pain and infections)
© 2016 Paul Billiet ODWS

4. Gene probes
Short pieces of DNA or RNA (100 – 1000 bases) complementary to a given sequence of nucleotides
Target DNA denatured (strands separate)
Probe added and binds to complementary sequence
Radioactive marker attached to probe so it can be identified
© 2016 Paul Billiet ODWS

5. FISHing for genes FISH = Fluorescent In Situ Hybridisation
Used to identify chromosomal abnormalities and mapping chromosomes
Image Credit: Journal of Medical Gdenetics FISH analysis of a chromosome abnormality where material is switched between chromosomes 9 and 11
© 2016 Paul Billiet ODWS

6. Pros Identifying potential parents of affected children
Identifying pre-symptomatic adults
© 2016 Paul Billiet ODWS

7. Cons Lab errors (false positives/false negatives)
Uncertainties in diagnosis from positive result
Lack of medical treatment in case of positive test
Risk of discrimination
© 2016 Paul Billiet ODWS