Gene: A discrete unit of hereditary information consisting of a specific nucleotide sequence of DNA

Genetic Counseling: A process of communication that deals with the occurrence or risk that a genetic disorder will occur in a family, help with testing and provide info people need to make informed choices

Genome: The complement of an organism's genes; an organism’s genetic material

Genetic Testing: The use of methods to determine if someone has a genetic disorder, will develop one, or is a carrier

Genetic Disorder: disease caused by abnormalities in an individual’s genetic material

Single Gener Disorder: mutations that occur in the sequence of one gene, protein product can’t carry out its normal job, inherited: autosomal dominant, recessive, Sex-linked, looks at genotype, ex: Sickle cell anemia

Multifactorial Disorder: combo of environmental and mutations in multiple genes, ex: heart disease, breast cancer

Chromosomal Disorder: missing, extra copies, breaks, deletions, rejoining, looks at karyotype, ex: down syndrome- the extra DNA makes extra proteins and that is what causes the unique physical features and internal problems

Mitochondrial Disorder: rare mutation in nonchromosomal DNA of mitochondria, passed solely from mother to child. the body has a difficult time making ATP. ex: leberś hereditary optic neuropathy

Carrier Screening: determines if the person is a carrier, shows recessive gene, ex: Tay-Sachs, sickle cell disease, takes blood goins thru PCR, then DNA sequencing and/or gel electrophoresis

Preimplantation Genetic Diagnosis (PGD): used in IVF to diagnose before the embryo is implanted into the uterus, a single cell is removed and examined, known autosomal dominant/sex-linked

Fetal Screening/Prenatal Diagnosis: allows parents to diagnose a genetic condition in their developing fetus, ex: amniocentesis, CVS, ultrasounds

Newborn Screening: detects genetic and medical conditions so that they can be treated early on

Polymerase Chain Reaction (PCR): A technique that involves copying short pieces of DNA and then making millions of copies in a short period of time

Denaturation: Step 1 of PCR, 94-95⁰C, template DNA is heated, the high temp causes the hydrogen bonds to break and the two strands to separate

Annealing: Step 2 of PCR, temperature decreases 45-60⁰C, the primers attach to the complementary sequence in the DNA template

Extension: Step 3 of PCR, 72⁰C, Taq polymerase adds nucleotides to the annealed primer.

Genotype: The genetic makeup of an organism, written, ex Tt

Phenotype: The physical and physiological traits of an organism, ex blue eyes

Single nucleotide polymorphism (SNP): One base-pair variation in the genome sequence

Restriction enzyme: A degradative enzyme that recognizes specific nucleotide sequences and cuts up DNA

Chorionic villus sampling (CVS): A technique for diagnosing genetic and congenital defects in a fetus by removing and analyzing a sample of the fetal portion of the placenta - diagnostic test for chromosomal abnormalities & genetic disorders but not detect neural tube defects or other birth defects
- removes cells from placenta via catheter through cervix or needle through abdomen
- invasive; 1 in 100 chance of miscarriage
- larger samples, faster results, and able to perform earlier in pregnancy than amniocentesis

Amniocentesis: A technique for determining genetic abnormalities in a fetus by the presence of certain chemicals or defective fetal cells in the amniotic fluid, obtained by aspiration from a needle inserted into the uterus - may be performed if there were abnormal results in a screening test or if parents have a family history of a specific genetic disorder (i.e.. cystic fibrosis)
- diagnostic test for chromosomal abnormalities, genetic disorders, neural tube defects, and fetal lung development
- removes cells from amniotic fluid around fetus via catheter needle through mother's abdomen
- invasive; 1 in 400 chance of miscarriage

Ultrasounds: Takes video of baby in womb, can determine fetus' age and sex, as well as physical defects. It is also used to see the heartbeat and diagnose a pregnancy.
- an instrument called a transducer emits high-frequency sound (inaudible to humans) and then records the echoes as the sound waves bounce back to determine the size, shape, and consistency of soft tissues and organs
- produces images on a computer screen

Duchenne Muscular Distrophy: Sex-linked recessive disorder, causes body to not make protein dystrophin, causing muscle weakness.

Cystic Fibrosis: Autosomal recessive, Causes problem in CFTR Protein, causing mucus to clog lungs, persistent cough, and other lung problems.

Huntington's Disease: Autosomal dominant, doesn't show symptoms until later
in life. Makes defective protein known as Huntington. It is a degenerative brain disease characterized by abnormal movements and a severe decline in thinking and reasoning skills.

Down Syndrome: Caused by a problem after/during conception (missing whole/partial chromosome 21). Characterized by small stature, physical defects, and mental retardation.

Leber hereditary optic neuropathy: Mitochondrial disorder creates a defective
enzyme responsible for converting oxygen, fats, and simple sugars to energy.
Characterized by vision loss.

Alzheimer's Disease: Early onset is autosomal dominant. Caused by a buildup
of beta-amyloid plaques and neurofibrillary tangles. Characterized by dementia and memory loss.

Screening Test: Shows how likely it is that the child may have a particular disorder or condition. - gives the odds but not a 100% confirmation (may lead to further diagnostic testing)
- could show false positives (results that show an abnormality but are later found to be false)
- minimum risk or impact on the mother or child

Diagnostic Test: Gives a definite answer as to whether or not a child will be born with a particular disorder or condition.
- results are from DNA taken from fetal cells
- some tests are invasive and risk the health of the fetus

Maternal Serum Screens: - noninvasive screening where blood is drawn from the mother
- does not diagnose a problem; only signals further testing should be done
- measures hormones
+ hCG
+ abnormal levels of other hormones suggest possibility of neural tube defects (i.e.. spina bifida) or chromosomal disorders (ie. Trisomy 21)

hCG (human chorionic gonadotropin): - only in pregnant women bc made by placenta
- also detected through ELISA urine test
- increasing levels in first trimester show normal pregnancy
- abnormal levels suggest chromosomal disorders like Trisomy 21

Nuchal Translucency Ultrasound: Special ultrasound measures nasal bone and fluid in back of neck
- shows risk of some birth defects

Cell-Free Fetal DNA Analysis: - noninvasive screening where blood is drawn from the mother
- tests fetus's DNA circulating in the mother's blood
- pinpoints baby's risk for a number of genetic disorders, including Down Syndrome
- identifies baby's blood type and gender

Glucose tolerance test: - used to see if the mother has developed gestational diabetes
- must fast for 14 hours prior
- patient drinks a sugary solution
- blood is drawn from finger prick once every three hours afterwards
- glucose levels are checked
- should increase quickly from the drink then gradually decrease over time

Gestational Diabetes: temporary disease occurring in some pregnancies where placental hormones cause high blood sugar

Plasmid: circular piece of double-stranded DNA, non-viral vector, not specific to any cell type, doesn’t integrate, doesn’t generate an immune response, better suited for ex vivo gene therapy

Lipopsome: plasmids packaged together, into liposome, miniature lipid-based packets similar to the cell’s own membrane when added to cells, these packets fuse to cell membranes, viral vector, not specific to any cell, when it enters the cell it's transported to the cell’s nucleus, doesn’t integrate, doesn’t generate an immune response, better suited for ex vivo gene therapy

Herpes Simplex Virus: agent behind oral and genital herpes, double-stranded DNA, viral vector, target and infect cells of the nervous system, max length of DNA inserted into HSV: 20,000 base pairs, doesn’t integrate, can stay in nucleus for a long time, causes an immune response

Adeno-Associated virus: doesn’t cause illness, single-stranded DNA, viral vector, infect dividing and nondividing, need assistance of a ‘helper’ virus to replicate, will integrate, max length of DNA inserted into AAV: 5,000 base pairs,

Adenovirus: causes common cold, double-stranded DNA, viral vector, infects dividing and nondividing very effectively, max length: 7,500 base pairs, can’t integrate, discarded from cell after a week or 2, causes immune response

Retrovirus: carry genetic material, ex. HIV, viral vector, only infect dividing cells, max length; 8,000 base pairs, RNA converts to DNA before going to nucleus, integrated, can cause immune response, can disrupt cell division

Gene therapy: The alteration of the genes of a person afflicted with a genetic disease

Vector: An agent (as a plasmid or virus) that contains or carries modified genetic material and can be used to introduce extra genes into the genome of an organism

3 strategies to gene therapy

INSERT: A functional gene is given to a patient, providing their body with the means to make a functional protein. The defective gene is still present but its effects are masked by the functional gene.

DISABLE: A dysfunctional gene is disabled, eliminating the impact of the protein

REPAIR: A dysfunctional gene is repaired so that it is able to produce a functional protein.

In Vitro Fertilization: A procedure in which gametes are fertilized in a dish in the laboratory, and the resulting zygote is implanted in the uterus for development

Preimplantation Genetic Testing (PGT): In assisted reproductive technology, the determination of genetic abnormalities in the embryo before it is transferred to the uterus