application a + b ! Flashcards
what does medical genetics focus on?
this focuses on diagnosis & managment of the medical, psychological, & social aspects of diseases involving mutations or influence of genes
what is medical genetics?
discipline involving a range of health professionals
what is family focus of medical genetics?
related to both medical care/ management of the pateint & forward-looking consideration of future of future offspring
what are the three types of hereditary disease?
-mendelian conditions
-chromosomal conditions
-multifactorial conditions
what are mendelian conditions?
-caused by mutation of a SINGLE gene
-autosomal dominant/recessive, X-linked dominant/recessive, Y-linked, & mitochondrial
-can be inherited by one or both parents or may be a new mutation
chromosomal conditions
-caused by an extra chromosome, a missing chromosome, duplication or deletion of a chromosome segment, & certain structural rearrangements of chromosomes; trisomy 21
-dev. and phys abnormalities can result due to human sensitivity Gene Dosage
-conditions may involve the autosomes or the sex chromosomes
what are multifactorial conditions?
-influenced bu multiple genes & environmental factors (diabetes)
-increased likelihood referred to as “inherited susceptibility” which varies
-variation is due to differing mutant allele frequencies in different populations
what are some different types of genetic testing?
-molecular analysis
-biochemical analysis
-chromosome analysis
explain molecular analysis
-tests DNA or RNA & is useful when there is suspicion of a specific mendelian condition
explain biochemical analysis
tests blood or tissues for absence of presence of certain proteins, as well as levels; also tests for variant proteins associated with the condition
explain chromosome analysis
tests for chromosomal causes of fetal or infant malformations, unexplained mental impairment or physical abnormalities at any age, & long-term infertility in adults
what does carrier testing do?
identifies individuals who are heterozygous for recessive conditions or have a chromosomal abnormality that could produce a condition in a future child
do carrier individuals have the genetic condition?
no
in some cases, carrier frequency is so high that testing is required as a public health effort, what is this the case for?
Tay-Sachs disease in Ashkenazi Jewish Populations
what is pre-symptomatic testing?
used for genetic conditions wiht a late age of onset, few diseases can be tested this way
by age 40, only about ____ of people
with the ________ ___________ mutant allele for ____________- disease WILL show the condition
50%; autosomal dominant; Huntington
what type of testing is mandated?
newborn testing
what is newborn testing?
mandated genetic tests that together require only a few drops of blood from a heel stick
what contains the list of genetic diseases recommended for testing?
Recommended Uniform Screening Panel (RUSP)
how many core hereditary conditions are there that nearly all states test for?
34
how many secondary conditions are there fpr each state to consider including alongside the core testing?
25
what is newborn genetic testing aiming to do?
-save lives
-reduce medical costs
-support the well-being of families
when a test is positive in newborn testing, what is followed?
immediate treatment
what is prenatal testing?
it is performed during pregnancy to detect a condition in a fetus including chromosomal abnormalities
is testing for prenatal testing invasive?
yes! they have to collect the blood of the fetus
how do we obtain the fetus’s genes in prenatal testing?
-placenta tissue through chronic villus sampling (CVS)
-amniotic fluid through amniocentesis
-some are diagnosed through ultrasound or maternal serum testing
what type of conditions are likely to be identified in prenatal testing?
-chromosomal conditions such as trisomy 21, as well as DNA mutations of specific genes
are chromosome conditions likely to be treatable?
no, this causes ethical conflicts about keeping or terminating the pregnancy
explain amniocentesis
this uses a needle to penetrate the uterus & placenta of a pregnant woman to get amniotic fluid, which contains fetus cells
-these cells are obtained between the 14th & 18th week of pregnancy & there is a risk of fetal loss
explain chronic villus sampling (CVS)
this uses a small tube passes transvaginally into the uterus to obtain tissue from the chorion on the outside of the placenta (fetal derived portion)
-this occurs as early as the 10th week of pregnancy & has a higher risk that amniocentesis
what is maternal serum screening?
this measures levels of three porteins in a pregnant woman’s blood between the 15th & 20th week of gestation
what are the three proteins that are associated with elevated risks of two trisomy conditions, & one that indicated possible neural tuve defect?
AFP level, uE3 level, & HCG level
is MSS a diagnostic test?
no! it is only screening- indicated increased likelihood of a condition rather than presence of a condition
if MSS suggests possible down syndrome in the fetus, what testing may be recommended
karyotyping
what is fetus cell sorting
this identifies & isolates fetal cells in maternal blood circulation for DNA & chromosome analysis
what has fetal cell sorting been used to identify?
- cystic fibrosis
- spinal muscular atrophy
what does preimplantation screening test for?
for hereditary diseases in fertilized embryos produced by in-vitro fertilization
what is IVF
a method of assisted reproduction for individuals & couples- expensive & not covered by ins. with this, ovulation is induced by hormone injections, eggs are removed from the surface of the ovaries, & the eggs are stored or used immediately for fertilization
when might an egg have one cell removed for preimplantation genetic screening using PCR?
to identify recessive genetic conditions when parents are normal carriers
what is the success rate for fertilized eggs implanted into the uterus?
15-40%
describe direct to consumer testing
offered by for-profit companies
-often duplicated medically available genetic carrier testing
-proved info about inheritance of genetic markers associated with certain hereditary conditions
what types of various types of personal genetic information testing is offered?
ancestry, carrier status, drug response, & likelihood or certain physical traits
how many medical conditions is 23andMe allowed to identify & who is more likely to develop those conditions?
10, individuals carrying certain single nucleotide polymorphism (SNP) (this only shows association does not cause conditions- only show association!
ELSI project
Genetic Information Nondiscrimination Act (GINA) of 2008
this restricts use of personal genetic information in issuing health insurance & life insurance, & in employment decisions
Affordable Care Act (ACA) of 2010
this excludes the use of personal genetic information in issuing health insurance as part of the clause preventing use of preexisting conditions as a basis for rejection
