- Genetic Testing -

- Genetic Counseling -

- Genetic Therapy -

By:AustinJustin

AmandaBrie

• Genetic testing allows the genetic diagnosis of vulnerabilities to inherited diseases, and can also be used to determine a person's ancestry. Every person carries two copies of every gene, one inherited from their mother, one inherited from their father.

NEWBORN SCREENINGPREDICTIVE and PRESYMPTOMATIC TESTING

DIAGNOSTIC TESTING

CARRIER TESTING

PRENATAL TESTING

FORENSIC TESTING

Genetic TestingGenetic Testing• Technology to detect and treat inborn

diseases - 1961.– Phenylketonuria - Sample blood from

newborn’s heel & test it for amino acid build-up of PKU.

• Today– Tandem mass spectrometry is used to

identify chemical imbalances of many inborn errors.

– Not costly, or difficult.

• Pros/Cons of newborn testing– Pro - detecting disease which is treatable – Con - detecting a disease which does not

have a known treatment.

Only ONE blood sample

Tests

For 50 conditions

Costs less than $100

– Biotinidase Deficiency

– Maple Syrup Urine Disease

– Congenital Adrenal Hyperplasia

– Congenital Hypothyroidism

– Glactosemia

– Homocystinuria

– Phylketonuria (PKU)

– Sickle cell and Other Hemoglobinopathies

Newborn Screening Tests:

Gene therapy using an adenovirus vector. A new gene is inserted into an adenovirus vector, which is used to introduce the modified DNA into a human cell. If the treatment is successful, the new gene will make a functional protein.

In theory it is possible to transform either somatic cells (most cells of the body) or cells of the germline (such as sperm cells, ova, and their stem cell precursors).

All gene therapy so far in people has been directed at somatic cells, whereasgermline engineering in humans remains only a highly controversial prospect.

For the introduced gene to be transmitted normally to offspring, it needs not only to be inserted into the cell, but also to be incorporated into the chromosomes by genetic recombination

There are a variety of different methods to replace or repair the genes targeted in gene therapy.

+ A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. This

approach is most common.

+ An abnormal gene could be swapped for a normal gene through homologous recombination.

+ The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal

function.

+ The regulation (the degree to which a gene is turned on or off) of a particular gene could be altered

Vectors in gene therapy:

Viruses

Retroviruses

Adenoviruses

Adeno-associated viruses

Envelope protein pseudotyping of viral vectors

Non-viral methods

Naked DNA

Oligonucleotides

Lipoplexes and polyplexes

Hybrid methods

Genetic counseling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning in order to prevent, avoid or ameliorate it. This complex process can be seen from diagnostic (the actual estimation of risk) and supportive aspects.

Genetic counseling can occur before:

Conception (i.e. when one or two of the parents are carriers of a certain trait),

During pregnancy (i.e. if an abnormality is noted on an ultrasound or if the woman will be over 35 at delivery),

After birth (if a birth defect is seen)

During childhood (i.e. if the child has developmental delay),

During adulthood (for adult onset genetic conditions such as Huntington’s disease or hereditary cancer syndromes).

References:• Ricki Lewis. Human Genetics Concepts and

Applications. New York: CareNet Medical Group. 2007.

• Wikipedia Foundation, Inc. Retrieved March 3, 2007. http://en.wikipedia.org/wiki/Main_Page