8: Down Syndrome

Question 1

What 5 heart conditions are common with down syndrome?

Answer 1

1. ASD (most common)
2. VSD
3. Tetralogy of Fallot
4. PDA
5. MVP (in adolescence)

Question 2

What are the 3 most common physical characteristics of down syndrome?

Answer 2

1. Generalized hypotonia
2. Epicanthal folds
3. Transverse palmar creases

Question 3

T/F Newborns weigh less, are typically shorter, and have smaller occipital frontal circumference as compared to normal infants.

Answer 3

True

Question 4

T/F Etiologies of down syndrome include frequency of intercourse.

Answer 4

True. Others are:

1. A genetic predisposition to nondisjunction.
2. Autoimmune action.
3. Hormonal alterations in aging women.
4. Viral disease.
5. Environmental factors.

Question 5

T/F In males there is an increase in urogenital conditions, including micropenis and hypospadias.

Answer 5

True

Question 6

Hypotonia includes laxity in ligament structure, which interferes with _____ development.

Answer 6

Gross motor

Question 7

This is made by the growing fetus and found in amniotic fluid, fetal blood, and maternal blood.

Answer 7

Alpha fetoprotein (AfP)

Question 8

Down syndrome screening is usually offered to women over age _____.

Answer 8

35

Question 9

Early signs include head tilt, torticollis, or deterioration in gait.

Answer 9

Atlantoaxial instability

Question 10

T/F The level of disability in down syndrome can vary.

Answer 10

True. Varies d/t extent of extra copy, genetic history, and pure chance.

Question 11

T/F Increased maternal age is a risk factor for down syndrome.

Answer 11

True

Question 12

How is down syndrome screened in the 1st trimester?

Answer 12

U/S nuchal translucency + blood test (PAPP-A and HCG).

Combination detects 82-87%.

Question 13

What is the life expectancy?

Answer 13

60

Question 14

There is an increased risk of what cancer?

Answer 14

Leukemia (10-20x)

Question 15

Name the MSK and motor ability defects (7).

Answer 15

1. Flat feet
2. Scoliosis
3. Dislocated hips
4. Atlantoaxial subluxation
5. Joint and muscle pain
6. Muscle fatigue
7. Wide-based gait

Question 16

When does the tendency to be overweight start?

Answer 16

2 yo, though at every age they are above 85%.

Question 17

Is nondisjunction more common in the maternal or paternal gamete?

Answer 17

88% from maternal. 8% from paternal. Chromosomes can fail to pair or fail to exchange genetic material, or both. Increases with maternal age.

Question 18

What cardiac defect may present in adolescents with down syndrome?

Answer 18

Mitral Valve Prolapse (57%)

Question 19

T/F Females have delayed onset of puberty.

Answer 19

False. Menarche at 12. Most have regular cycles with ovulation. This can be a concern, as children have 50% chance of having down syndrome.

Question 20

What new test provides high accuracy and few false positives?

Answer 20

Free fetal DNA test. Requires blood draw since fetal cells circulate in maternal blood.

Question 21

What is the most common cardiac anomoly?

Answer 21

Atrioventricular septal defect (ASD)

Question 22

Name screening recommendations for down syndrome (7).

Answer 22

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

Question 23

What are associated GI malformations (3)?

Answer 23

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).

Question 24

AFP can help measure and detect what 4 things?

Answer 24

1. Neural tube defects
2. Some renal/urinary tract defects
3. Turner’s Syndrome
4. Down Syndrome

Question 25

This is made by the placenta and fetal liver.

Answer 25

Estriol

Question 26

To detect atlantoaxial instability, when should 1 set of cervical spine films be taken?

Answer 26

3-5 yo (Special Olympics participants need periodic screening)

Question 27

How does mosaicism occur?

Answer 27

Abnormal cell division AFTER fertilization.

Question 28

In translocation, part of chromosome 21 becomes _____ before or at conception.

Answer 28

Attached onto another chromosome

Question 29

T/F Most have moderate IQ of 40-55, but cognitive function can decline with age.

Answer 29

True. May also have behavior disorders, depression, and autistic-like symptoms.

Question 30

Down syndrome is an extra copy of chromosome _____.

Answer 30

21

Question 31

When is velocity of linear growth most reduced (2)?

Answer 31

6-24 months and again in adolescence.

Question 32

This product is made by the placenta.

Answer 32

HCG

Question 33

Which leukemia usually has a good outcome?

Answer 33

Acute lymphocytic leukemia (ALL)

Question 34

What is the most effective screening test?

Answer 34

Integrated testing. Uses both 1st and 2nd trimester tests. 5% false positives.

Question 35

What are the 2 invasive diagnostic tests and when are they performed?

Answer 35

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).

Question 36

Is down syndrome more frequent in males or females?

Answer 36

Males

Question 37

Now that down syndrome children live to an older age, what are we discovering as additional risks (2)?

Answer 37

1. Premature aging

2. Alzheimer’s

Question 38

More fluid collects here when abnormalities are present.

Answer 38

Nuchal translucency