Genetic Testing RaeAnna Illman, John Hurlburt, Duane Goehring, Kim Silvernale

Gene Therapy Gene Therapy is delivering replacement genes to correct the problem at it’s source.

Three Phases of Treatment Evolution Treating the gene to cure a disease is still not the norm despite HGP advances Replacement of missing proteins with material from donors. Obtaining pure proteins using recombinant DNA technology. Deliver replacement genes

Gene Therapy With recent advances, gene therapy has now moved to the treatment of common diseases. Gene therapy began by treating complex, uncommon, and inherited diseases.

3 Models for Gene Therapy : In-vivo Ex-vivo In-situ

Germline and Somatic Therapies Germline gene therapy alters the DNA of a gamete or fertilized ovum. Somatic gene therapy corrects only the cells that an illness affects. Picorray therapy places “artificial” genes on a microchip

Methods of Delivery Physical – microinjection, particle bombardment, electroporation. Chemical – liposomes which secure genetic cargo and can penetrate plasma membranes. Biological- Vectors; remove the virus from its membrane and put in its place corrective genes. (very flexible)

Proteins Gene therapy uses proteins that are missing to treat the phenotype This has mitigated issues with ADA deficiency and white blood cell problems A lasting treatment is the alteration of Progenitor cells which make up one in roughly a billion bone marrow cells. Potential problems: Mutations remain in the genotype Not a dynamic fix which will last throughout the germline Although the protein is fixed, the gene remains mutated

Setbacks to Gene Therapy The body may reject the foreign or altered genes. Unused amino acids let off a nitrogen gas which mixed with hydrogen to form ammonia that goes into the bloodstream and then into the brain. Method of Transportation = inject unaffected genes into a dead virus which will replicate multiple times and fill the gaps created by affected genes. Gene therapies became difficult to continue after so many failures. New laws are passed to keep them from repeating

Canavan Disease Because no treatment exists, canavan disease made it a unique case study for gene therapy It’s a neurological disease, so brain scans make the progress much easier and safer to track Treatment must be constant and timely.

Genetic Testing 2 basic steps: 1) identifying the condition 2) taking action against the mutant genes.

Newborn Screening Genetic counseling involves pedigrees and helps in weighing the options of how to conceive Testing is not expensive because testing for certain disorders in the metabolism requires a simple blood test

Genetic Counseling 2 major reasons: 1) prenatal counseling 2) a disease in the family. It is a “shared deliberation and decision making between the counselor and the client.” Confidentiality and “duty to warn” relatives is debated

Great Promise There is more of a need now for medical genetics due to the rare orphan diseases. The more physicians find out about these diseases, the better chance of new treatments for them. Gene therapy progress has been painstakingly slow.

The delivered genes do not always go where intended. New gene defects. Ways to correct many of the disease Revealed a complexity to genome structure. Minor setbacks...

In conclusion... Although there are draw backs, gene therapy is working. Patients with muscular dystrophy, cystic fibrosis, and SCID have cells that accepted and expressed therapeutic genes. The challenge is find the right vector to deliver a sustained, targeted, and safe genetic correction.

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