Ch. 30 Chromosomal Abnormalities Flashcards
_______are the structures, located in each cell in our body, that hold our genes.
Chromosomes
an error in either the number or structure of chromosomes
chromosomal abnormality
The normal cell has ____chromosomes or two pairs of ____.
46; 23
_______ is a condition in which there are an abnormal number of whole chromosomes. Specifically, an aneuploid has too many or too few chromosomes.
Aneuploidy
chromosomal aberration in which there is a third chromosome 18
Edwards syndrome
a cell having three copies of an individual chromosome
trisomy
Turner syndrome, also referred to as _______ X, is a different type of chromosomal abnormality in which the fetus has only one sex chromosome.
monosomy
a chromosomal aberration where one sex chromosome is absent; may also be referred to as monosomy X
Turner syndrome
_______ and ______ have been suspected to increase the likelihood of chromosomal abnormalities.
Environmental factors; maternal age
is a structural feature that differs from the norm. An example of an ______ is agenesis of the corpus callosum in which there is congenital absence of an important midline brain structure.
anomaly
the congenital absence of corpus callosum that may be partial or complete
agenesis of the corpus callosum
a group of clinically observable findings that exist together and allow for classification. These signs and symptoms are linked to each other in some way.
syndrome
_______has clinically identifiable signs such as a flat facial profile and a transverse crease in the palm of the hand. An example of symptoms of _______would be developmental delays and hearing loss.
Down syndrome
a structural abnormality that results from an abnormal development
malformation
_________is a congenital brain malformation that is thought to be caused by a developmental deviation in the roof of the fourth ventricle.
Dandy–Walker malformation
congenital brain malformation in which there is enlargement of the cisterna magna, agenesis of the cerebellar vermis, and dilation of the fourth ventricle
Dandy–Walker malformation
The three laboratory values that typically comprise the triple screen are ______, _______, and ______.
MSAFP, estriol, and hCG.
AFP is produced in the ______and fetal liver. Estriol and hCG are produced by the _______.
yolk sac; placenta
This simple blood test can reveal gender and is also highly accurate in detecting chromosomal anomalies, including trisomies 21, 18, and 13 and sex chromosome abnormalities, as early as 9 weeks’ gestation.
cell-free DNA testing
the most common cause of abnormal serum screening tests is _______ of the pregnancy.
incorrect dating
Advanced maternal age is considered to be ______ years or older.
35
an analysis of fetal chromosomes; reveals the morphology and number of chromosomes
Fetal karyotyping
the form and structure of an organism
morphology
During pregnancy, a sample of maternal blood, amniotic fluid, or tissue from the placenta can be used for fetal karyotyping. There are three main procedures used to obtain material for fetal karyotyping: ______,_______,_______
(i) chorionic villi sampling (CVS), (ii) amniocentesis, and (iii) cordocentesis
prenatal test used that obtains placental tissue for chromosomal analysis
chorionic villi sampling
a surgical procedure in which amniotic fluid is extracted for genetic testing or removed when there is an accumulation of an excessive amount of fluid around the fetus
amniocentesis
prenatal test that obtains fetal blood for chromosomal analysis
cordocentesis
_______ typically the earliest procedure that can be performed during a pregnancy for fetal karyotyping. With _____, a small amount of _______is obtained for chromosomal testing. Can be performed transabdominally or transvaginally (transcervical) between ____ and ____ gestational weeks. Under sonographic guidance, a needle or plastic catheter is placed into the placental mass for the aspiration of trophoblastic cells
CVS; chorionic villi; 10 and 13
the cells that surround the gestation that produce human chorionic gonadotropin
trophoblastic cells
Some research links a possible association between CVS performed less than 10 weeks and _______abnormalities.
fetal limb
Amniocentesis is typically used for genetic purposes between ____and ____ weeks. Some facilities may offer this procedure to patients as early as 10 weeks, although some studies suggest that it should not be done before 15 weeks because of an increase in fetal complications.
15 and 20
An amniocentesis is performed ______ with sonographic guidance. The physician inserts a 20 to 22G needle through the abdomen and into the amniotic sac to remove amniotic fluid for testing. The most common side effects of this procedure are ______ and ______. Rarely, patients experience vaginal spotting, amniotic fluid leakage, or amnionitis. (may take as many as 3 wks for results)
transabdominally; uterine contractions and cramping
inflammation of the amniotic sac secondary to infection
amnionitis
An amniocentesis may also be performed to assess the fetal ____for maturity by obtaining fluid and testing the lecithin-to-sphingomyelin ratio (L/S ratio). Also, a ______ amniocentesis can be performed to remove excess amniotic fluid or to distend the amniotic cavity with more fluid when scant fluid is noted around the fetus.
lungs; therapeutic
Cordocentesis, also referred to as _______ (PUBS) or fetal blood sampling, is performed transabdominally after 17 weeks.
percutaneous umbilical cord sampling
For PUBS, a needle is placed through the maternal abdomen and into the umbilical vein. The segment of the cord that is most often accessed is at the cord insertion point into the ______.
placenta
A sample of fetal blood is removed. PUBS has been associated with fetal _______ and _______ at the sampling site. It also carries a _____ fetal loss rate compared to amniocentesis. PUBS allows for _____ detection of chromosomal anomalies, because it requires only 48 to 72 hours for analysis.
bradycardia, hemorrhage, higher, rapid
fingerlike projections of gestational tissue that attach to the decidualized endometrium and allow transfer of nutrients from the mother to the fetus
chorionic villi
A cell having three times the normal haploid number. There are 69 chromosomes.
Triploid
A situation in which some cells have an abnormal number of chromosomes whereas others do not.
Mosaic
A cell having only one of an individual chromosome.
Monosomy
A cell having only one member of each pair of chromosomes
Haploid
A cell having the normal pair of each chromosome. There are 46 chromosomes in this situation. Normal cells are diploid, with the exception of the gametes.
Diploid
_________or trisomy 21, is the most common chromosomal abnormality. It occurs in 1 in 500 to 800 pregnancies.
Down syndrome
Maternal Serum Screening Results of _________
Low MSAFP
Low estriol
High hCG
High inhibin A
Low PAPP-A
Down Syndrome
For down syndrome maternal serum screening outcomes yield evidence of elevated _____ _______ levels, whereas all other laboratory values are reduced.
hCG and inhibin A
enlargement of the renal pelvis; also referred to as pelviectasis
pyelectasis
incomplete or arrested development of a structure
hypoplastic
round skull shape
Brachycephaly
the bending of the fifth finger toward the fourth finger
Clinodactyly
buildup of cerebrospinal fluid that results in an enlargement of one or more of the ventricles within the brain
ventriculomegaly
enlargement of the tongue
Macroglossia
fetal hydrops caused by congenital fetal anomalies and infections
Nonimmune hydrops
fluid accumulation around the heart in the pericardial cavity
Pericardial effusion
a large space between the first and second toes
Sandal gap
Sonographic Findings of ________
1.Absent nasal bones (hypoplastic nose)
2.Brachycephaly
3.Clinodactyly
4.Duodenal atresia
5.Mild ventriculomegaly
6.Echogenic intracardiac focus
7.Hyperechoic (echogenic) bowel
8.Macroglossia
9.Nonimmune hydrops
10.Nuchal thickening 6 mm or larger between 15 and 21 weeks
11.Thickened nuchal translucency
12.Pericardial effusion
13.Pyelectasis
14.Sandal gap
15.Shortened limbs (humerus and femur)
16.Ventricular septal defects (VSDs)
17.Widened pelvic angles
Down Syndrome
he word part omphalo means ________
umbilical region.
cysts located within the lateral ventricles of the brain, specifically in the choroid plexus
choroid plexus cysts
a small mandible and recessed chin
micrognathia
abnormal curved shape of the sole of the feet
rocker-bottom feet
an anterior abdominal wall defect where there is herniation of the fetal bowel and other abdominal organs into the base of the umbilical cord
omphalocele
Maternal Serum Screening Results of _________
Low AFP
Low estriol
Low hCG
Low inhibin A
Low PAPP-A
Edwards Syndrome
Sonographic Findings of _______
1.Strawberry-shaped skull
2.Agenesis of the corpus callosum
3.Choroid plexus cyst
4.Hypoplastic cerebellum
5.Enlarged cisterna magna
6.Hydrocephalus
7.Micrognathia
8.Small, low-set ears
9.Esophageal atresia
10.Spina bifida
11.Clenched hands, overlapping index finger, fixed wrists
12.Cardiac defects (including VSD and tetralogy of Fallot)
13.Omphalocele
14.Nonimmune hydrops
15.Diaphragmatic hernia
16.Renal anomalies
17.Single umbilical artery
18.Feet abnormalities (rocker-bottom feet, clubfeet)
Edwards Syndrome
the increased volume of cerebrospinal fluid within the ventricular system
Hydrocephalus
congenital absence of part of the esophagus
Esophageal atresia
a birth defect in which there is incomplete closure of the spine
Spina bifida
the herniation of the abdominal contents into the chest cavity through a defect in the diaphragm
Diaphragmatic hernia
a malformation of the bones of the feet in which the feet are inverted and rotated medially, and the metatarsals lie in the same plane as the tibia and fibula; singular is clubfoot
clubfeet
_________ includes a strawberry-shaped skull, choroid plexus cysts, micrognathia, rocker-bottom feet, omphalocele, clenched fists, and single umbilical.
Edwards syndrome
Holoprosencephaly and abnormal facies are common findings with __________
Patau syndrome or trisomy 13.
a group of brain abnormalities consisting of varying degrees of fusion of the lateral ventricles, absence of the midline structures, and associated facial anomalies
Holoprosencephaly
the features or appearance of the face
facies
fusion of the orbits
cyclopia
having more than the normal number of fingers or toes
polydactyly
small head
Microcephaly
an abnormal division in the lip
cleft lip
the abnormal development of the soft and/or hard palate of the mouth where there is a division in the palate
cleft palate
small eye or eyes
microphthalmia
reduced distance between the orbits
hypotelorism
incomplete development of the left ventricle, resulting in a small or absent left ventricle
hypoplastic left heart
the dilation of the renal collecting system resulting from the obstruction of the flow of urine from the kidney(s) to the bladder; also referred to as pelvocaliectasis or pelvicaliectasis (dilation of the renal pelvis and calices)
hydronephrosis
The majority of fetuses diagnosed with _______, or _______, die either before birth or shortly after birth.
Edwards syndrome, trisomy 18
this is almost a uniformly fatal condition, as the newborn typically dies in the neonatal period
Patau syndrome (Trisomy 13)
Maternal Serum Screening Results of _______
Maternal serum is not always beneficial and depends upon the anomaly present (cell-free DNA is helpful)
Patau Syndrome
Sonographic Findings of __________
1.Microcephaly
2.Polydactyly
3.Holoprosencephay
4.Ventriculomegaly
5.Hydrocephalus
6.Agenesis of the corpus callosum
7.Small, low-set ears
8.Facial anomalies (cyclopia, cleft lip, cleft palate, microphthalmia, hypotelorism)
9.Cardiac defects (hypoplastic left heart and echogenic intracardiac focus)
10.Omphalocele
11.Nonimmune hydrops
12.Renal anomalies (hydronephrosis, echogenic enlarged kidneys)
13.Single umbilical artery
14.Clubfeet
Patau Syndrome
*Single umbilical artery in pelvis. Use ____ Doppler transverse image of pelvis demonstrating a single umbilical artery adjacent to one side of the bladder (BL). On the contralateral side, no umbilical artery is seen arising from the iliac artery.
color
Maternal Serum Screening Results of ______
Elevated hCG in the presence of a molar pregnancy
Triploidy
First-Trimester Sonographic Findings of _______
1.Cystic spaces seen within an enlarged placenta (molar pregnancy)
2.Fetal demise (IUFD/aka stillbirth)
3.Bilateral ovarian theca lutein cysts
Triploidy
Second- and Third-Trimester Sonographic Findings of ________
1.Holoprosencephaly
2.Dandy–Walker malformation
3.Agenesis of the corpus callosum
4.Hydrocephalus
5.Facial abnormalities (microphthalmia and micrognathia)
6.Small, low-set ears
7.Cardiac defects
8.Renal anomalies
9.Intrauterine growth restriction (small abdomen)
10.Omphalocele
11.Syndactyly (third and fourth fingers)
12.Single umbilical artery
13..Clubfeet
Triploidy
Because there are multiple major structural anomalies associated with ________, most of the fetuses with ________ die in the first trimester or early second trimester. There are two types of _______ (type I and type II).
triploidy
Often, a partial ______is found with a triploid fetus, thus resulting in a markedly elevated ______ level and bilateral ovarian ________.
molar pregnancy; hCG; theca lutein cysts
also referred to as gestational trophoblastic disease; is associated with an abnormal proliferation of the trophoblastic cells, enlargement of the placenta, and elevated levels of human chorionic gonadotropin
molar pregnancy
functional ovarian cysts that are found in the presence of elevated levels of human chorionic gonadotropin; also referred to as a theca luteal cysts
theca lutein cysts
webbed fingers or toes
syndactyly
a fetus that is below the 10th percentile for gestational age (small for gestational age) and whose growth is impeded for some reason
intrauterine growth restriction
_____________ is a disorder found in females. It may also referred to as 45,X or monosomy X because, most often, the paternal sex chromosome is missing
Turner syndrome
a mass found in the neck that is the result of an abnormal accumulation of lymphatic fluid within the soft tissue
nuchal cystic hygroma
the abnormal accumulation of fluid in the pleural space
pleural effusions
a buildup of fluid under the skin
subcutaneous edema
excessive fluid in the peritoneal cavity
ascites
the loss of a pregnancy before 20 gestational weeks
spontaneous abortion
imperfect or abnormal development of the ovaries
Ovarian dysgenesis
Maternal Serum Screening Results of ______
Low estriol
Low AFP
Low hCG (with hydrops)
Low inhibin A (with hydrops)
Low PAPP-A
Turner Syndrome
_______is a chromosomal abnormality in which the fetus has 69 chromosomes instead of the normal 46.
Triploidy
With Turner syndrome maternal serum screening reveals decreased levels of all laboratory findings when ______ is present
hydrops
the attachment of the lower poles of the kidneys by a band of renal tissue that crosses the midline of the abdomen
horseshoe kidneys
failure of the kidney to develop; may be unilateral or bilateral
renal agenesis
the narrowing of the aortic arch
coarctation of the aorta
the benign enlargement of the male breast; typically located posterior to the areola
gynecomastia
Sonographic Findings of ________
1.Increased nuchal translucency
2.Cystic hygroma (large,septated)
3.Renal anomalies (horseshoe kidneys and renal agenesis)
4.Cardiac defects (coarctation of the aorta)
5.Nonimmune hydrops
Turner Syndrome
Nonimmune ______ is the buildup of fluid within at least two fetal body cavities. Therefore, ascites, pleural effusions, pericardial effusion, and subcutaneous edema are all common findings with Turner syndrome
hydrops
Turner syndrome is an often-fatal condition that leads to ________ in the first or second trimester. It does, however, have a reported incidence of 1 in 2,500 to 5,000 live female births.
spontaneous abortion
_____ dysgenesis, webbed neck, short stature, motor deficits, hearing loss, and renal anomalies are common in those persons who do survive birth and progress into adulthood. (w/ Turner syndrome)
Ovarian
_________, or 47,XXY, is a male chromosomal anomaly that can result in hypogonadism, small testis, tall stature, long legs and arms, and gynecomastia. These individuals also tend to suffer from subnormal intelligence.
Klinefelter syndrome
