8: Down Syndrome Flashcards

1
Q

What 5 heart conditions are common with down syndrome?

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

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

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

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

A

True

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4
Q

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

A

True. Others are:

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

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

A

True

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6
Q

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

A

Gross motor

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7
Q

In nondisjunction, a _____ is produced with an extra copy of chromosome 21 (24 chromosomes total).

A

Gamete

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8
Q

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

A

Alpha fetoprotein (AfP)

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9
Q

Down Syndrome is caused by a random event during the formation of _____.

A

Sex cells

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10
Q

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

A

35

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11
Q

Is nondisjunction or translocation responsible for the majority of down syndrome?

A

Nondisjunction (95%)

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12
Q

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

A

Atlantoaxial instability

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13
Q

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

A

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

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14
Q

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

A

True

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15
Q

How is down syndrome screened in the 1st trimester?

A

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

Combination detects 82-87%.

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16
Q

What is the life expectancy?

A

60

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17
Q

T/F There are more than 50 diagnostic physical characteristics of down syndrome.

A

False. There are more than 50, but they are not diagnostic.

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18
Q

How is down syndrome detected in the 2nd trimester (2)?

A
  1. Multiple marker screening at 15-20 weeks (AFP + Estriol + HCG)
  2. Quad screen at 15-20 weeks (AFP + Estriol + HCG + Inhibin A)
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19
Q

The child has the usual 2 copies of chromosome 21, but also has additional material from 21 attached to another chromosome.

A

Translocation

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20
Q

There is an increased risk of what cancer?

A

Leukemia (10-20x)

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21
Q

Name the MSK and motor ability defects (7).

A
  1. Flat feet
  2. Scoliosis
  3. Dislocated hips
  4. Atlantoaxial subluxation
  5. Joint and muscle pain
  6. Muscle fatigue
  7. Wide-based gait
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22
Q

When does the tendency to be overweight start?

A

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

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23
Q

Is nondisjunction more common in the maternal or paternal gamete?

A

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

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24
Q

What cardiac defect may present in adolescents with down syndrome?

A

MVP (57%)

25
Q

T/F Females have delayed onset of puberty.

A

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

26
Q

How does nondisjunction happen during formation of the egg?

A

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.

27
Q

What new test provides high accuracy and few false positives?

A

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

28
Q

The chance of down syndrome is 1 in _____ for women above 45 years of age.

A

19

29
Q

What is the most common cardiac anomoly?

A

Atrioventricular septal defect (ASD)

30
Q

Name screening recommendations for down syndrome (7).

A
  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
31
Q

What are associated GI malformations (3)?

A
  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).
32
Q

What is the incidence of down syndrome?

A

1:691 (6,000 new cases/year)

33
Q

AFP can help measure and detect what 4 things?

A
  1. Neural tube defects
  2. Some renal/urinary tract defects
  3. Turner’s Syndrome
  4. Down Syndrome
34
Q

Only some cells have the extra copy of chromosome 21.

A

Mosaicism

35
Q

Recent data suggest paternal age over _____ increases risk.

A

42

36
Q

This is made by the placenta and fetal liver.

A

Estriol

37
Q

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

A

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

38
Q

How does mosaicism occur?

A

Abnormal cell division AFTER fertilization.

39
Q

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

A

Attached onto another chromosome

40
Q

T/F Down syndrome is more common in Caucasians.

A

False. Occurs across all races and ethnic groups.

41
Q

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

A

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

42
Q

Down syndrome is an extra copy of chromosome _____.

A

21

43
Q

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

A

6-24 months and again in adolescence.

44
Q

This product is made by the placenta.

A

HCG

45
Q

Which leukemia usually has a good outcome?

A

Acute lymphocytic leukemia (ALL)

46
Q

What is the most effective screening test?

A

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

47
Q

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

A
  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).
48
Q

This results from laxity between C1 and C2.

A

Atlantoaxial instability

49
Q

Nondisjunction is a _____ event while cells are dividing.

A

Meiotic

50
Q

80% of down syndrome babies are born to women _____.

A

Under 35

51
Q

Is down syndrome more frequent in males or females?

A

Males

52
Q

Which hypothalamic dysfunction is common?

A

Growth hormone defects

53
Q

This form of down syndrome can be inherited.

A

Translocation

54
Q

How effective is the quad screen at detecting down syndrome?

A

81% (7% false positives)

55
Q

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

A
  1. Premature aging

2. Alzheimer’s

56
Q

Which type of transmission is not genetic (2)?

A

Nondisjunction

Mosaicism

57
Q

More fluid collects here when abnormalities are present.

A

Nuchal translucency

58
Q

T/F Mosaicism can have varying levels of down characteristics.

A

True. The more cells affected the greater the number of characteristics.

59
Q

Only about _____% of children with down syndrome have translocation.

A

1-2%