Down Syndrome Vignette

Question 1

1. Describe the chromosomal abnormalities associated with Down Syndrome and how to test for them.

Answer 1

Trisomy 21: 95% of patients with down syndrome
-Parents usually have normal chromosomes; recurrence risk is 1:100+ risk of maternal age

Unbalanced Translocation between chromosome 21 and another acrocentric chromosome 3-4% of patients with DS (important to check karyotype of parents)

Mosaic Tri 21 (mixture of normal cells and cells containing Tri 21): 1-2% of patients with DS—phenotypes are less severe

Question 2

2. Describe the physical features (Phenotype) seen in a patient with Down Syndrome.

Answer 2

Common physical features:

• -growth parameters are normal usually
• midfacial hypoplasia (underdeveloped)
• upslanting palpebral fissures
• small ears
• large appearing tongue
• low muscle tone, increased joint mobility
• short fingers

Question 3

3. Recognize the medical problems seen in patients with Down Syndrome.

Answer 3

Cardiac Issues
50% of DS patients
Atrioventricular canal
ECG in newborns recommended

Gastrointestinal
10-15% have structural abnormalities: esophageal atresia, duodenal atresia, hirschsprungs
-functional GI issues; feeding problems, constipation, GERD, celiac disease

Ophthalmologic

• blocked tear ducts
• myopia
• lazy eye
• nystagmus
• cataracts

ear, nose and throat problems

• chronic ear infections
• deafness
• chronic nasal congestion
• enlarged tonsils and adenoids

Endocrine

• thyroid disease
• insulin dependent diabetes
• alopecia areta
• reduced fertility (normal puberty)

Orthopedic problems

• hips
• joint subluxation
• atlantoaxial subluxation

Hematologic issues
-myeloproliferative disorder in the newborn
-increased risk of leukemia 12-20x
iron deficiecny anemia

developmental issues

• hypotonia effects gross motor development
• spectrum of intellectual disability–average is mild-moderate disabilities
• speech problems: importance of sign language

neurologic

• hypotonia-specturm from mild-severe
• seizures-especially infantile spasms

psyhciatric issues

• depression
• early alzheimers
• autism (1/10 patients with DS)