NU 116 EXAM 4 Module VIII With
Complete Solution
Genetic disorder - ANSWER An abnormal condition that a person inherits
through genes or chromosomes
chromosome - ANSWER coiled strands of DNA carrying genes
- somatic cells are diploid (46)
- gametes are haploid (23)
somatic cells - ANSWER Any cells in the body other than reproductive cells,
46 chromosomes - diploid
gamete cells - ANSWER sex cells, 23 chromosomes - haploid
karyotype - ANSWER pictorial analysis of an individual's chromosomes
*placental tissue/amniocentesis can provide this*
Normal female karyotype - ANSWER 46, XX, no Y chromosomes
Normal male karyotype - ANSWER 46, XY
trisomy - ANSWER 3 copies of a chromosome instead of 2
monosomy - ANSWER missing a chromosome, individual has 45
chromosomes
mosaicism - ANSWER -Occurs after fertilization
-Results in an individual with 2 different cell lines, each having a different
,chromosomal number
-More common in sex chromosomes
turner syndrome - ANSWER A chromosomal disorder in females in which
either an X chromosome is missing, making the person XO instead of XX, or
part of one X chromosome is deleted.
two examples of mosaicism - ANSWER turner syndrome and klinefelter
syndrome
Klinefelter syndrome - ANSWER A chromosomal disorder in which males
have an extra X chromosome, making them XXY instead of XY.
Abnormalities of Sex Chromosomes - ANSWER - occur in early embryonic
stage
- examples include Turner's syndrome and Klinefelter's syndrome
autosomal dominant inheritance - ANSWER - 50% chance of passing on the
gene if one parent is affected
- males and females are equally affected
- varying degrees of presentation
- disorders include: huntington's disease, myotonic dystrophy, fragile X
syndrome
Huntington's disease - ANSWER chronic brain disease
s/s include tremors, impaired thinking, problems swallowing
Myotonic dystrophy - ANSWER muscular dystrophy, presenting in adulthood
s/s include weakness in feet/legs/hands, abnormal HR, muscle pain
,examples of autosomal dominant disorders - ANSWER - huntington's disease
- myotonic dystrophy
- fragile x syndrome
autosomal recessive inheritance - ANSWER Carrier parents have a
- 25% chance of producing an affected child
- 25% chance of passing on abnormal gene
- *If child is clinically normal, 50% change child is a carrier*
- males and females equally affected
examples include: sickle cell, cystic fibrosis, and some metabolic disorders
X-linked recessive inheritance - ANSWER - no male to male transmission
- 50% chance carrier mother will pass abnormal gene to sons (affected)
- 50% chance carrier mother will pass abnormal gene to daughters (carrier)
- fathers affected cannot pass disorder to sons, but all daughters become
obligate carriers
examples: hemophilia, muscular dystrophy, colorblindness
X-linked dominant inheritance1 - ANSWER VERY RARE
- no male to male transmission
- can be lethal in utero, newborn periods (Rett syndrome)
- affected fathers will have affected daughters but not sons
- vitamin D resistant rickets
, multifactorial inheritance - ANSWER - no clear pattern of inheritance
- often a sex bias (eg: pyloric stenosis + males, cleft palate + females)
- increased incidence when multiple family members affected, increased risk
with CLOSEST relatives
- cleft palate, heart defect, spina bifida, dislocated hips, clubfoot, pyloric
stenosis
responsibility of nurse in prenatal diagnostic testing - ANSWER - conselling
before screening/testing
- available to all women presenting for prenatal care
- recognize emotional impact on family
Genetic Ultrasound - ANSWER form of diagnostic test, best at 16-20 weeks
maternal serum screening - ANSWER Determines risk for Down syndrome,
trisomy 18, or open spina bifida
noninvasive prenatal testing through cell-free fetal DNA - ANSWER testing
for woman of advances maternal age
genetic amniocentesis indications - ANSWER - maternal age 35+
- previous child born with chromosomal abnormality
- parent carrying chromosomal abnormality
- mother carrying X linked disease
- both parents carrying autosomal recessive disease
- family hx of neural tube defects
Complete Solution
Genetic disorder - ANSWER An abnormal condition that a person inherits
through genes or chromosomes
chromosome - ANSWER coiled strands of DNA carrying genes
- somatic cells are diploid (46)
- gametes are haploid (23)
somatic cells - ANSWER Any cells in the body other than reproductive cells,
46 chromosomes - diploid
gamete cells - ANSWER sex cells, 23 chromosomes - haploid
karyotype - ANSWER pictorial analysis of an individual's chromosomes
*placental tissue/amniocentesis can provide this*
Normal female karyotype - ANSWER 46, XX, no Y chromosomes
Normal male karyotype - ANSWER 46, XY
trisomy - ANSWER 3 copies of a chromosome instead of 2
monosomy - ANSWER missing a chromosome, individual has 45
chromosomes
mosaicism - ANSWER -Occurs after fertilization
-Results in an individual with 2 different cell lines, each having a different
,chromosomal number
-More common in sex chromosomes
turner syndrome - ANSWER A chromosomal disorder in females in which
either an X chromosome is missing, making the person XO instead of XX, or
part of one X chromosome is deleted.
two examples of mosaicism - ANSWER turner syndrome and klinefelter
syndrome
Klinefelter syndrome - ANSWER A chromosomal disorder in which males
have an extra X chromosome, making them XXY instead of XY.
Abnormalities of Sex Chromosomes - ANSWER - occur in early embryonic
stage
- examples include Turner's syndrome and Klinefelter's syndrome
autosomal dominant inheritance - ANSWER - 50% chance of passing on the
gene if one parent is affected
- males and females are equally affected
- varying degrees of presentation
- disorders include: huntington's disease, myotonic dystrophy, fragile X
syndrome
Huntington's disease - ANSWER chronic brain disease
s/s include tremors, impaired thinking, problems swallowing
Myotonic dystrophy - ANSWER muscular dystrophy, presenting in adulthood
s/s include weakness in feet/legs/hands, abnormal HR, muscle pain
,examples of autosomal dominant disorders - ANSWER - huntington's disease
- myotonic dystrophy
- fragile x syndrome
autosomal recessive inheritance - ANSWER Carrier parents have a
- 25% chance of producing an affected child
- 25% chance of passing on abnormal gene
- *If child is clinically normal, 50% change child is a carrier*
- males and females equally affected
examples include: sickle cell, cystic fibrosis, and some metabolic disorders
X-linked recessive inheritance - ANSWER - no male to male transmission
- 50% chance carrier mother will pass abnormal gene to sons (affected)
- 50% chance carrier mother will pass abnormal gene to daughters (carrier)
- fathers affected cannot pass disorder to sons, but all daughters become
obligate carriers
examples: hemophilia, muscular dystrophy, colorblindness
X-linked dominant inheritance1 - ANSWER VERY RARE
- no male to male transmission
- can be lethal in utero, newborn periods (Rett syndrome)
- affected fathers will have affected daughters but not sons
- vitamin D resistant rickets
, multifactorial inheritance - ANSWER - no clear pattern of inheritance
- often a sex bias (eg: pyloric stenosis + males, cleft palate + females)
- increased incidence when multiple family members affected, increased risk
with CLOSEST relatives
- cleft palate, heart defect, spina bifida, dislocated hips, clubfoot, pyloric
stenosis
responsibility of nurse in prenatal diagnostic testing - ANSWER - conselling
before screening/testing
- available to all women presenting for prenatal care
- recognize emotional impact on family
Genetic Ultrasound - ANSWER form of diagnostic test, best at 16-20 weeks
maternal serum screening - ANSWER Determines risk for Down syndrome,
trisomy 18, or open spina bifida
noninvasive prenatal testing through cell-free fetal DNA - ANSWER testing
for woman of advances maternal age
genetic amniocentesis indications - ANSWER - maternal age 35+
- previous child born with chromosomal abnormality
- parent carrying chromosomal abnormality
- mother carrying X linked disease
- both parents carrying autosomal recessive disease
- family hx of neural tube defects
