Microdeletion Syndromes

Question 1

Clinical findings in cri-du-chat syndrome

Answer 1

1. Microcephaly
2. Moderate to severe intellectual disability
3. High-pitched crying/mewing
4. Epicanthal folds
5. Cardiac abnormalities (VSD)

Question 2

Williams syndrome is due to…

Answer 2

Congenital microdeletion of long arm of chromosome 7 (deleted region includes elastin gene).

Question 3

Clinical findings in Williams syndrome

Answer 3

1. Distinctive “elfin” facies
2. Intellectual disability
3. Hypercalcemia (due to increased sensitivity to vitamin D)
4. Well-developed verbal skills
5. Extreme friendliness with strangers
6. Cardiovascular problems

Question 4

Cri-du-chat syndrome is due to…

Answer 4

Congenital microdeletion of short arm of chromosome 5

Question 5

Microdeletion at chromosome 22q11 produces variable presentations including…

Answer 5

1. Cleft palate
2. Abnormal facies
3. Thymic aplasia –> T-cell deficiency
4. Cardiac defects
5. Hypocalcemia (secondary to parathyroid aplasia)