chap 6 - start of unit 2

Question 1

frequency and significance of genetic and developmental diseases

Answer 1

3-4% of newborns have birth defects
- causes
65% unknown
20% genetic
5% chromosomal
10% environmental
- 250,000 born with serious birth defects
- half of all miscarriages due to chromosome abnormalities

Question 2

developmental disease

Answer 2

birth defect
- orginating in the embryo and fetus, disease affects normal maturation,

Question 3

genetic disease

Answer 3

disease caused by abnormal DNA, inherited, occur during gamete development

Question 4

errors of morphogenesis

Answer 4

due to genetics, environmental or teratogens

Question 5

teratogens

Answer 5

harmful drugs and chemicals that will cause harm to developing fetus
ex: cigarettes, alcohol, radiation, maternal infections, rubella, herpes simplex virus

Question 6

fetal alcohol syndrome

Answer 6

1:1000 births
- mom consumes alcohol - how much determines the severity
- fetal growth restriction, CNS abnormalities, distinctive facial features

Question 7

monogenetic

Answer 7

single gene, classified as: autosome or sex chromosome, dominant or recessive
examples: sickle cell anemia, cystic fibrosis

Question 8

polygenetic

Answer 8

many genes plus the environment
- multifactorial
examples: cleft lip and cleft palate, spina bifida

Question 9

chromosomal

Answer 9

wrong number or wrong structure of the chromosomes
- karyotype useful for visualizing - mapping out of the chromosomes
- alterations in chromosome structure or number
chromosome abnormalities
- leading cause of genetic disease
- leading cause of intellectual impairment
- leading cause of pregnancy loss

Question 10

types of chromosomal change

Answer 10

aneuploidy, deletions, translocations

Question 11

aneuploidy

Answer 11

having the wrong number, can be detected in an amniocentesis and chorionic villus sampling - because these take cells from the fetus

Question 12

nondisjuction

Answer 12

the chromosomes don’t pull apart like they should
- can occur in either the egg or the sperm

Question 13

stages of developmentt

Answer 13

fertilization - embryonic period - fetal period - perinatal period - infancy - childhood - adolescence

Question 14

embryonal period

Answer 14

first 8 weeks after fertilization

Question 15

fetal period

Answer 15

weeks 9-38, organs mature and get bigger, most sensitive to teratogens because that is when the organs are developing

Question 16

perinatal period

Answer 16

two weeks before birth to one month after birth

Question 17

infancy

Answer 17

the first year of life

Question 18

childhood

Answer 18

after a year old up until puberty

Question 19

organogensis

Answer 19

organs are formed

Question 20

when does organogenesis occur?

Answer 20

embryonic perriod

Question 21

most common embryonic and fetal diseases

Answer 21

congenital heart defects
- often come attention around the time of birth
- cyanosis, murmur

Question 22

cyanosis

Answer 22

blue lips, blue fingernail bed, the oxygenated and deoxygenated blood mix together due to defect within the heart

Question 23

perinatal diseases

Answer 23

“around birth”
- prematurity most important cause of death
complications - low birth weight, brain development, the lungs are also the last to develop

Question 24

prematurity

Answer 24

gestational age correlates directly with surivial

Question 25

prematurity complication examples

Answer 25

cerebral palsy

Question 26

cerebral palsy

Answer 26

associated with gestational age in some cases
- group of disorders affecting learning, muscle tone, movement, motor skills, hearing and seeing
nonprogressive

Question 27

diseases of infancy

Answer 27

major causes of infant death:
- congenital and chromosomal abnormalities
- prematurity and low birth weight
- sudden infant death syndrome
- complications of maternal diseases
- diseases of the placenta and umbilical cord

Question 28

sudden infant death syndrom

Answer 28

unexpected, sudden death of a child under age 1
risk factors
- sleeping on the stomach
- being around cigarette smoke before or after birth
- cosleeping
- premature birth
- having a sibling who had SIDS
- mothers who use illegal drugs
- being born to a teen mother
- no prenatal care
- living in poverty situations

Question 29

diseases of childhood and adolescence

Answer 29

differ from diseases of older age groups in relative frequency
- neoplasms less common
accidents and infections more common - most common cause of death for children under 5 is accidents
- some genetic diseases manifest in childhood

Question 30

amniocentesis

Answer 30

detects about 1,000 of the more than 5,000 know chromosomal and biochemical problems, ultrasound is used to follow needles movement
risk - some pregnancies are lost
recommended for = fetus around 15-16 weeks

Question 31

chorionic villi sampling

Answer 31

chorionic villi = projections of the placenta
performed during 10-12th week of pregnancy
- earlier results from amniocentesis
- less accurate than amniocentesis
- does not test amniotic fluid
- cannot test for neural tube defects
- placental mosaicism
- greater risk of pregnancy loss

Question 32

ultrasound

Answer 32

detection of major structural abnormalities

Question 33

genetic disease

Answer 33

disease caused by a change in DNA sequence away from the normal sequence
- may be inherited from either parent
- errors in cell division, meiosis or mitosis
classifications: chromosomal disorders, autosomal dominant, autosomal recessive, and sex linked

Question 34

examples of genetic diseases

Answer 34

down syndrome, sickle cell disease, marfan syndrome, cystic fibrosis, phenylketonuria, duchenne muscular dystrophy

Question 35

down syndrome

Answer 35

trisomy 21
- most common chromosome abnormality
- single most common cause of genetic intellectual impairment
- error in cell division
- 95% due to nondisjunction meiosis I
- egg is source of extra 21 in 95% of cases
main risk: maternal age

Question 36

clinical features of down syndrome

Answer 36

• intellectual impairment - variable
• round face, slanted eyes
• congenital heart disease
• intestinal defects
• shorter life expectancy
• increased risk for alzheimer’s disease

Question 37

turner syndrome

Answer 37

sex chromosome abnormality
- 45, X
female phenotype
characteristics –> shorter in stature, webbing in the neck, no intellectual impairment, the internal sex organs do not develop correclty, not uterus, ovaries, they will also be sterile
- this is because X wasn’t pulled apart correctly so they only have the 1 X chromosome
aneuploidy

Question 38

klinefelter syndrome

Answer 38

XXY - an extra X copy in a male
male phenotype
- characteristics –> typically taller then normal, long extremities and digits, can have breast development, will be sterile because they don’t have normal production of sperm

Question 39

autosomal dominant inheritance

Answer 39

gene is expressed if only one copy is present
- one allele is dominant
an affected person has a 50% chance of passing gene to child
examples = huntington’s disease and marfan syndrome

Question 40

marfan syndrome

Answer 40

defect in collagen synthesis, several different systems are affected
- skeleton = tall, long appendages and extremities
- heart valves = dont snap shut tightly, also impacts the blood vessels, they might not be strong enough against the pressure of blood vessels
- eyes - retina can detach in the back of the eye

Question 41

autosomal recessive inheritance

Answer 41

need two copies of the defective gene
- parents of affected are usually heterozygous carriers

Question 42

cystic fibrosis

Answer 42

most common AR disorder affecting caucasians - very common to be a carrier as well
- mutation in the chloride channel
- results in: mainly affects the lungs and GI tract - lack of movement of chloride decrease the movement of sodium which in result decreases the water movement of the lungs, mucus in the lungs gets thick and sticky and can clog up the bronchioles which can increase the chance of infection
- low life expectancy –> reduced down to their 30s

Question 43

sickle cell anemia

Answer 43

mutation in hemoglobin molecule, altering its shape - more likely to clump and stick together which can cause blockages to organs, simple change to a base in the DNA

Question 44

phenylketonuria

Answer 44

mutation in phenylalanine hydroxylase enzyme absent, resulting in phenylalanine wants to convert to tyrosine but needs phenylalanine hydroxylase to do so
- results in intellectual impairment
- treatment => avoiding phenylalanine, testing in newborns mandatory in all 50 states

Question 45

sex linked inheritance

Answer 45

x chromosome is large
x linked diseases are mutations carried on the X chromosome

Question 46

duchenne muscular dystrophy

Answer 46

symptoms usually present around 3 years of age
- delayed development
- loss of muscular skills
- clumsiness/frequent falls
- difficulty walking and running - wheelchair bound by 12 years
- ultimately effects diaphragm - death usually occurs around 30
- diagnosis typically around 16 months - 5 years