Down Syndrome - Elias L1

Question 0

What is the chromosomal error that cases trisomy 21 and what increases the risk of this happening?

Answer 0

Error in nondisjunction

Maternal age ≥35-40

Question 1

What are the three genotypes associated with DS and what percentages of pts present with each?

Answer 1

Trisomy 21 95%
Unbalanced Translocation 3-4% (e.g. t(21,14))
Mosaic Tri 21 1-2% milder presentation usually

Question 2

First trimester screening for Trisomy 21?

Answer 2

Ultrasond measrement of nuchal folds (extra folds = bad)
Beta-hCG + PAPP-A

(human chorionic gonadotropin, pregnancy-associated plasma protein A)

Question 3

2nd trimester trisomy 21 screening?

Detection rate in 2nd trimester?

Answer 3

Quad Screen
	beta-hCG
	AFP (alpha-fetoprotein)
	unconjugated estriol
	inhibin level

Detection rate at 2nd trimester = 95%

Question 4

Estimated incidence of trisomy 21?

Answer 4

1 in 700

Question 5

At what maternal age is the risk become high?

Answer 5

35 and up the curve shoots up.

Question 6

Recurrance risk?

Answer 6

1/100 + maternal age risk (see graph)

age 40 risk is 1/100

—> recurrance risk is 1/50

Question 7

List some common physical finding of a DS infant.

Answer 7

1. growth parameters usually normal
2. midfacial hypoplasia
3. upslanting palpebral fisures, epicanthal folds
4. small ears
5. tounge seems large but really the oral compartment is small
6. low muscle tone (hypotonia), double jointed (increased joint mobility)
7. short fingers, transverse palmer crease, 5th finger incurving (clinodactyly), increased space btwn 1st & 2nd toes
8. Eustation tubes too small -> ear infections

Question 8

Incidence of cardiac issues in DS pts?

Some common cardiac issues?

Answer 8

50% of DS pts have cardiac issues

Wide range of cardiac defects:
Atrioventriclar Canal (common, needs surgical repair)
hole btwn atria
hole btwn ventricles

Question 9

Incidence of GI tract issues in DS pts?

3 most common ones?

Answer 9

10 - 15% of infants have GI tract structural anomalies

Esophageal atresia
Dodenal atresia
Hirschsprng’s Disease (sympathetics non-functional in lower 1/3 of bowel, constipation)

Question 10

What are the functional GI issues in DS pts?

Answer 10

feeding problems - very common
constipation - extremely common due to hyptonia
GERD - very common
Celiac Disease (screen with TTG +IgA)

Question 11

What are the opthalmologic problems in DS pts?

Answer 11

blocked tear ducts
myopia (near sightedness)
strabismus (lazy eye)
nystagmus
cataracts - congenital or dev. over time

Question 12

What fraction of DS pts have ear, nose and throat problems?

Common ENT problems?

Answer 12

2/3

chronic ear infections (small eustatian tubes)
deafness (both conductive (fluid) and sensorineural)
chronic nasal congestion
enlarged tonsils & adnoids = Obstructive Sleep Apnea, also related to obesity

Question 13

What are some common endocrine disorders in DS pts?

Answer 13

Thyroid = most common endocrine problem seen; usually hypothyroidism but also Grave's disease
Insulin Dependent Diabetes (type 1)
Alopecia Areata (hair falls out in patches)
Reduced fertility

Question 14

Joint issues in DS pts?

Answer 14

hips dislocation
joint subluxation
**atlantoaxial subluxation - rare but bad = high level cervical paralysis

Question 15

Hematologic Issues in DS pts?

Answer 15

Myeloproliferative disorder in newborns
increased risk of leukemia - 12 to 20 times
iron deficiency anemia

Question 16

Developmental Isses in DS pts?

Answer 16

hypotonia = gross motor activities affected
intellectual disabilities - average is mile-moderate disabilities (50 IQ)
Speech problems - poss. due to hypotonia; tongue not fit in mouth or hearing issues or some comb. of the three
use sign language

Question 17

Neurologic issues in DS pts?

Answer 17

hypotonia - mild to severe possible

seizures - especially infantile spasms

Question 18

Psychiatric Issues in DS pts?

Answer 18

Depression
early Alzheimers
Autism 1 in 10 pts