Genetic Lecture exam 3 Flashcards
Why preform genetic testing
-Establish or confirm a genetic diagnosis
-Reproductive decision making: seeing what conditions your kids are predisposed to
-Prediction of future disease
-Aid in med mgmt: seeing what drugs are effective
Paradigm shift
-Going from gathering history, diagnosis hypothesis and confirming it with a test
-To ordering a test to forming a hypothesis and diagnosis based on it while doing a detailed history to confirm it
Genome
A person’s genetic blueprint
Genotype
Inherited from the parents, your “code”
Phenotype
Expression of the genotype based on environmental factors
-Can indicate something is wrong with the genotype
Aneuploidy
Chromosomal abnormality, a cell that does not contain a multitude of 23 chromosomes
-Essentially one of the chromosome pairs has an extra or one less
-Trisomy or monosomy
-Occurs due to a non-disjunction typically
Trisomy
Contains three copies in one chromosome
-Its better to have 3 than 1
Disjunction
-Normal
-Separation of chromosomes during cell division, into the typical pairs
Nondisjunction
-Abnormal
-Improper separation of chromosomes into their pairs, leading to trisomy and monosomy
-Usually the cause of the aneuploidy
-Occurs during meiosis 1/2
Cell free DNA
Genetic testing, prenatally that is minimally invasive
-Done through a maternal blood sample, as it contains floating fetal DNA
-The fetal cells when they perform apoptosis leaves DNA floating in the bloodstream, which enters the maternal bloodstream
-Significantly less invasive than amniocentesis or taking a fetal blood sample
Non invasive prenatal test (NIPT)
-Cell free DNA test
-Test for Trisomy 13, 18, 21 as well as sex chromosome differences
Down Syndrome
-Trisomy 21
-Risk increases with maternal age (1/800 births)
Characteristics
-Mentally challenged
-Low nasal bridge
-Epicanthal folds
-Protruding tongue
-Poor muscle tone
Turner syndrome
-Sex chromosome aneuploidy: can be tested prenatal
Female with only one X chromosome
Characteristics
-Absence of ovaries (sterile)
-Short stature
-Webbing of the neck (Neck looks super thick)
-Edema
-Underdeveloped breast, wide nipples
Klinefelter syndrome
-Sex chromosome aneuploidy: can be tested prenatal
Individual with 2X 1Y
Characteristics
-Male appearance
-Has female like breast
-Small testes
-Sparse body hair
-Long limbs
Indications for prenatal or ped testing
-Developmental delays
-Intellectual disabilities
-Dysmorphic features
-Family history
-FTT
-Atypical growth
-Cafe au lait spots
-Congenital defects
-Hearing loss
Seizures
-Atypical sexual development
Genetics
-Observing one gene at a time and finding an effect
-Where we are
Genomics
-Observing the entire genome and the interactions between genes and how they affect development
-Where we wanna go
Adenine (A) bond with
Thymine (T)
Guanine (G) bonds with
Cytosine (C)
Protein
50+ amino acids
Peptide
2 or more amino acids