Chapter 10 & 12 Flashcards
1
Q
What are the 3 patterns of single gene inheritance patterns?
A
- autosomal dominant
- Autosomal Recessive
- X Linked
2
Q
Autosomal Dominant Traits, transmission and examples
A
- trait on dominant gene on non-sex chromosome
- can be asymptomatic carriers
- can be transmitted via: men who have offspring in fifties, are carriers and pass new mutation to offspring, can inherit mutations on both genes if both parents are carriers.
- Hutington Disease and Achondroplasia (dwarfism, congenital)
3
Q
Autosomal Recessive Trait, transmission and examples
A
- person receives 2 copies of recessive gene
- rare
- recessive disorders are severe, patients usually don’t live long enough to reproduce
- CF and PKU, tay-sachs, sickle cell, and blood groups
- 1/4 chance of having recessive disorder if both parents are carriers
4
Q
X-Linked recessive traits, transmission and examples
A
- males usually show full effect of X-linked recessive disorder due to only having 1 X chromosome, only 1 gene is needed
- females carry trait while males are affected
- Females can only inherit if female has single X chromosomal (turners syndrome), or born from affected father and carrier mother.
- Colorblindness, hemophilia
- varying degrees of severity
5
Q
Numerical Chromosomal Abnormalities
A
-involved added or missing chromosomes
6
Q
Trisomy
A
- numerical chromosomal abnormalities
- extra single chromosome totally 47
- most common is Triosmy 21/down syndrome where there is 3 pairs of chromosome
- risk increased with maternal age >35
7
Q
Monosomy
A
- numerical chromosomal abnormalities
- missing single chromosome totally 45
- only condition that is compatible with life is Tuner Syndrome (single x chromosome)
8
Q
Polyploidy
A
- numerical chromosomal abnormalities
- one or more extra sets of chromosomes
- results in spontaneous abortion but occasionally seen in live born infant
9
Q
Structural Abnormalities
A
-structure of one or more chromosomes may be -abnormal or missing or added DNA or rearranged
10
Q
Translocation
A
- part of a chromosome is attached to another
- offspring may receive too much or too little chromosome material at conception or spontaneously in offspring of parents with no translocation.
- Structural abnormalities
11
Q
Fragile X Syndrome
A
- Fragile X syndrome is when a area on the X chromosome is weakened and causes intellectual disability.
- Translocation abnormalities
- It is inherited wit the X-Linked dominant pattern.
- Males mostly affected but females can as well but they have 2 X chromosome.
12
Q
Multifactorial Disorders characteristics and risk for occurrence
A
- most common birth defect
- caused by interaction of genetic susceptibility and environmental factors during development (such as mother must have inadequate folic acid intake and genetic susceptibility for the child to have spinal bifida.
- can be single, isolated, primary or secondary
- heart defects, neural tube defects, cleft lip and palette, pyloric stenosis
- Factors that affect risk include: number of close relatives, severity of disorder, sex, geographic, seasonal variations
13
Q
Teratogens
A
- agents that cause a birth defect or increase likelihood of its development
- infections from viruses/bacteria
- drugs, tobacco, alcohol
- aminioglycosides
- anticonvulsants
- Statins
- anitthyroid
- Folic Acid antagonist
- Lithium
- Mercury
- Tetracycline
- warfarin
- ionizing radiation
- maternal hyperthermia
14
Q
Rubella Teratogen
A
-immunization at least 4 weeks prior pregnancy to avoid damage to fetus
15
Q
Drugs and Other Substances Teratogen
A
- Class A has no fetal risk
- Class X poses fetal harm
- Avoid Alcohol
- No FDA regulation on botonical products
16
Q
Ionizing Radiation Teratogen
A
-radiologic test should be done within first 2 weeks following missed period or have lead on lower abdomen
17
Q
Maternal Hyperthermia Teratogen
A
- avoid saunas or hot tubs
- mothers temp can increases uncontrollably during illness
18
Q
Oligohydramnios
A
- abnormally small volume of amniotic fluid which reduces the cushion surrounding the fetus and can cause deformations
- interferes with fetal lung development
- mechanical development to fetal development
19
Q
Fibrous Amniotic Bands
A
- may result from tears in inner sac of fetal membranes and can cause intrauterine limp amputation
- mechanical disruptions to fetal development
20
Q
Preconception Screening for Genetic Counsling
A
- done prior conception
- family history
- examination of photographs
- physical examination
- carrier testing
- people from ethnic groups with higher incidence of some disorders
- chromosome analysis
- DNA analysis
21
Q
Prenatal Diagnosis for Fetal Abnormalities Screening for Genetic Counseling
A
- maternal test to screen for abnormalities
- chorionic villus sampling
- amniocentesis
- ultrasound
- percutaneous umbilical blood sampling
22
Q
Physical Diagnosis for an Infant with Birth Defect for Genetic Counseling
A
- done after birth
- physical examination
- radiologic procedures
- chromosome analysis
- DNA analysis
- Test for metabolic disorders such as PKU and CF
- Hemoglobin analysis for disorders such as sickle cell disease
- immunologic testing for infections
- autopsy
23
Q
What is the time frame for the embryonic period and what happens during this time frame?
A
- 3 to 8 weeks
- formation of organs
24
Q
Week 1
A
-fertilization and implantation begins
25
Week 2
- implantation is complete
- Outer cells (trophoblast) becomes placenta
- Inner cells become embyronic disk
26
Week 3
- Period missed
- embryonic disk develops in 3 layers (ecotderm, mesoderm, and endotherm
- CNS develops
- Neural tube is open
- 2 chamber heart with 1st beat around 21st day
27
Week 4
- embryo is C shaped
- tail
- face and respiratory tract formation begins
- eye, nose, inner eardevelopment
- extremity buds appear
28
Week 6
- head is flexeddue to rapid brain growth
- eyelid development
- blood formation in liver
- lobe in lungs develop
- abdominal cavity containsmostly of liver andkidneys with intestines in umbilical cord
- 4 chamber heart
29
Week 7
- Face more human looking
- intestines growing quicker than abdominal v=cavity
- trunk elongates but still c shaped
30
Week 8
- taste buds develop
- eyelids fuse
- heart beat detectable with ultrasound
- testes or ovaries develop
- webs between fingers and toes
31
Fetal Period time frame
-week 9 to birth
32
Week 10
- may be possible to detect heartbeat with doppler
- blood produced in spleen
- digestive tract patent from mouth to anus
- intestines within abdominal cavity
33
Week 12
- surface of brain is smooth without sulci or gyri
- nasal and palate complete
- heart beat should be detectable via doppler
- sucking reflex present
- kidneys produce urine
- lanugo
34
Week 16
- eyes face forward
- fetus swallows amniotic fluid and produces meconium
- may feel fetal movements
- fingerprints developing
35
Week 20
- heartbeat should be detectable with fetoscope
- peristalsis developed
- testes descend into scrotum
- vernix on thin skin
- brown fat developed
- movement may be felt by practitioner
36
Week 24
- surfactant production started
- fetus active
- eyebrows and lashes present
- survival is possible
37
Week 28
- sulci and gyri present
- eyelids no longer fused
- blood formation in bone marrow
- sufficient surfactant
- fetus assumes head down position
38
Week 32
- maturation of nervous system resulting in FHR variability
- skin is pigmented per race
- lanugo disappearing
39
Week 38
- sulci and gyri develop
- visual acuity 20/600 at birth
- fetus plump with smooth skin
- vernix present in major body creases
- ear cartilage firm
40
When does cleft palate occur
-week 5-7
41
Autosomal Dominant Examples
- marfans
- huntington
- polydactyly
- dwarfism
42
Autosomal Recessive Examples
- PKU
- Galactosemia
- Maple syrup urine disease
- CF
- Tay-Sachs
- Sickle Cell
