Chromosomal Abnormalities

Question 1

What types of aneuploidies are there?

Answer 1

• trisomy
• monosomy
• microdeletions
• microduplications

Question 2

What are some common signs at birth for a baby with Down Syndrome?

Answer 2

• significant hypotonia
• single palmar crease
• uniques facial features (small ears, upward slanting of eyes, large protruding tongue)
• congenital heart defects

Question 3

What are the long term qualities of those with Down Syndrome?

Answer 3

• lowered IQ
• lowered life expectancy –> 50-60yrs
• good social skills, happy
• Alzheimer’s disease –> beta-amyloid proteins encoded on that chromosome
• 90% due to maternal chromosome

Question 4

What are the qualities of Edwards Syndrome?

Answer 4

• life expectancy is days to weeks
• 90% have congenital cardiac abnormalities
• polydactyly

Question 5

What are the qualities of Patau Syndrome?

Answer 5

• life expectancy
• 90% have congenital cardiac abnormalities
• cleft lip and palate

Question 6

What is Turner Syndrome?

Answer 6

45X

• infertility
• short
• female

Question 7

What is Klinefelter Syndrome?

Answer 7

47XXY
-30% have breast enlargement
-infertility
-extra chromosome comes from mom and dad equally
XYY
-fertile, tall, emotionally immature/impulsive
XXX
-fertile
-increased learning disabilities
-delayed development
-weak muscle tone

Question 8

Describe Wolf-Hirschhorn and Cri-du-chat

Answer 8

4p (W-H) and 5p (CDC) deletions

• severe learning disabilities
• larynx is underdeveloped in Cri-du-chat

Question 9

Describe Fragile X Syndrome

Answer 9

tip of X looks fragile due to trinucleotide repeats

-second most common cause of mental retardation

Question 10

Describe Angelman Syndrome

Answer 10

-inappropriate laughter, convulsions, poor coordination, severe learning disabilities

Question 11

Describe Prader-Willi Syndrome

Answer 11

• floppiness

- poor feeding in infancy and excessive eating after 2Yo –> obesity