Flashcards in 8: Down Syndrome Deck (59):
What 5 heart conditions are common with down syndrome?
1. ASD (most common)
3. Tetralogy of Fallot
5. MVP (in adolescence)
What are the 3 most common physical characteristics of down syndrome?
1. Generalized hypotonia
2. Epicanthal folds
3. Transverse palmar creases
T/F Newborns weigh less, are typically shorter, and have smaller occipital frontal circumference as compared to normal infants.
T/F Etiologies of down syndrome include frequency of intercourse.
True. Others are:
1. A genetic predisposition to nondisjunction.
2. Autoimmune action.
3. Hormonal alterations in aging women.
4. Viral disease.
5. Environmental factors.
T/F In males there is an increase in urogenital conditions, including micropenis and hypospadias.
Hypotonia includes laxity in ligament structure, which interferes with _____ development.
In nondisjunction, a _____ is produced with an extra copy of chromosome 21 (24 chromosomes total).
This is made by the growing fetus and found in amniotic fluid, fetal blood, and maternal blood.
Alpha fetoprotein (AfP)
Down Syndrome is caused by a random event during the formation of _____.
Down syndrome screening is usually offered to women over age _____.
Is nondisjunction or translocation responsible for the majority of down syndrome?
Early signs include head tilt, torticollis, or deterioration in gait.
T/F The level of disability in down syndrome can vary.
True. Varies d/t extent of extra copy, genetic history, and pure chance.
T/F Increased maternal age is a risk factor for down syndrome.
How is down syndrome screened in the 1st trimester?
U/S nuchal translucency + blood test (PAPP-A and HCG).
Combination detects 82-87%.
What is the life expectancy?
T/F There are more than 50 diagnostic physical characteristics of down syndrome.
False. There are more than 50, but they are not diagnostic.
How is down syndrome detected in the 2nd trimester (2)?
1. Multiple marker screening at 15-20 weeks (AFP + Estriol + HCG)
2. Quad screen at 15-20 weeks (AFP + Estriol + HCG + Inhibin A)
The child has the usual 2 copies of chromosome 21, but also has additional material from 21 attached to another chromosome.
There is an increased risk of what cancer?
Name the MSK and motor ability defects (7).
1. Flat feet
3. Dislocated hips
4. Atlantoaxial subluxation
5. Joint and muscle pain
6. Muscle fatigue
7. Wide-based gait
When does the tendency to be overweight start?
2 yo, though at every age they are above 85%.
Is nondisjunction more common in the maternal or paternal gamete?
88% from maternal. 8% from paternal. Chromosomes can fail to pair or fail to exchange genetic material, or both. Increases with maternal age.
What cardiac defect may present in adolescents with down syndrome?
T/F Females have delayed onset of puberty.
False. Menarche at 12. Most have regular cycles with ovulation. This can be a concern, as children have 50% chance of having down syndrome.
How does nondisjunction happen during formation of the egg?
The 2 copies of chromosome 21 fail to separate. This causes a total of 47 chromosomes when the normal gamete combines with the nondisjunction gamete.
What new test provides high accuracy and few false positives?
Free fetal DNA test. Requires blood draw since fetal cells circulate in maternal blood.
The chance of down syndrome is 1 in _____ for women above 45 years of age.
What is the most common cardiac anomoly?
Atrioventricular septal defect (ASD)
Name screening recommendations for down syndrome (7).
1. EKG and cardiac U/S: Birth
2. Hearing: 6/12 months, then yearly
3. Thyroid (T4/TSH): 6 months, then yearly
4. Eyes: 6 months, then yearly
5. Teeth: 2 years, then yearly
6. Sleep study: 3-4 yo (earlier if needed)
7. Neck X-rays: 3-5 yo
What are associated GI malformations (3)?
1. Hirschprung's disease (affects large intestine and causes problems passing stool).
2. Pyloric stenosis (blocks food from entering small intestine).
3. Duodenal atresia (absence or complete closure of a portion of the lumen of the duodenum).
What is the incidence of down syndrome?
1:691 (6,000 new cases/year)
AFP can help measure and detect what 4 things?
1. Neural tube defects
2. Some renal/urinary tract defects
3. Turner's Syndrome
4. Down Syndrome
Only some cells have the extra copy of chromosome 21.
Recent data suggest paternal age over _____ increases risk.
This is made by the placenta and fetal liver.
To detect atlantoaxial instability, when should 1 set of cervical spine films be taken?
3-5 yo (Special Olympics participants need periodic screening)
How does mosaicism occur?
Abnormal cell division AFTER fertilization.
In translocation, part of chromosome 21 becomes _____ before or at conception.
Attached onto another chromosome
T/F Down syndrome is more common in Caucasians.
False. Occurs across all races and ethnic groups.
T/F Most have moderate IQ of 40-55, but cognitive function can decline with age.
True. May also have behavior disorders, depression, and autistic-like symptoms.
Down syndrome is an extra copy of chromosome _____.
When is velocity of linear growth most reduced (2)?
6-24 months and again in adolescence.
This product is made by the placenta.
Which leukemia usually has a good outcome?
Acute lymphocytic leukemia (ALL)
What is the most effective screening test?
Integrated testing. Uses both 1st and 2nd trimester tests. 5% false positives.
What are the 2 invasive diagnostic tests and when are they performed?
1. CVS after 10 weeks (Karyotyping of placental tissue from cervix or abdomen).
2. Amniocentesis at ~15 weeks (Karyotyping of fetal skin cells or amniocytes in amniotic fluid).
This results from laxity between C1 and C2.
Nondisjunction is a _____ event while cells are dividing.
80% of down syndrome babies are born to women _____.
Is down syndrome more frequent in males or females?
Which hypothalamic dysfunction is common?
Growth hormone defects
This form of down syndrome can be inherited.
How effective is the quad screen at detecting down syndrome?
81% (7% false positives)
Now that down syndrome children live to an older age, what are we discovering as additional risks (2)?
1. Premature aging
Which type of transmission is not genetic (2)?
More fluid collects here when abnormalities are present.
T/F Mosaicism can have varying levels of down characteristics.
True. The more cells affected the greater the number of characteristics.