Lecture 9: Cytogenetics I Flashcards
What is the karyotype for Trisomy 13?
47,XX,+13 (female)
47,XY,+13 (male)
What is the eponym for Trisomy 13?
Patau
What are the clinical features of Trisomy 13?
- Midline deformations
- Microcephaly
- CHD
- Scalp defects (cutis aplasia)
- Holoprosencephaly
- Microphtalmia
- Cleft palate
- Polydactyly
- Renal anomalies
List all three trisomies in order of their incidence rates.
Trisomy 13: 1-2 in 10,000 (low)
Trisomy 18: 1-2 in 6,000 (medium)
Trisomy 21: 1 in 700 (high)
What is the prognosis for Trisomy 13?
Poor, 95% die in the first six months.
What is the karyotype for Trisomy 18?
47,XX,+18 (female)
47,XY,+18 (male)
What is the alternative name for Trisomy 18?
Edwards
What are the clinical features of Trisomy 18?
- Small size
- Small head circumference
- Congenital heart defects
- Overlapping fingers
- Rocker bottom feet
What is the prognosis for Trisomy 18?
Poor, 95% die within 12 months.
What is the karyotype for Trisomy 21?
47,XX,+21 (female)
47,XY,+21 (male)
What is the alternative name for Trisomy 21?
Down
What are the clinical features of Trisomy 21?
- Flat facial profile
- Upslanted palpebral fissures
- Anomalous auricles
- Nuchal skin fold
- Single palmar crease
- Clinodactyly
- Hypotonia
- Hyperflexible joints
- Intellectual Disability
- Sandle gap
What is the prognosis for Trisomy 21?
Live into 50s/60s.
What is the karyotype of Turner Syndrome?
45,X
What are the clinical features of Turner Syndrome?
- Lymphedema in infancy
- Bicuspid aortic valve
- Coarctation of aorta
- Short stature
- Gonadal regression (streak ovaries)
- Low posterior hairline
- Webbed neck
- Widely spaced nipples
- Horseshoe kidney
- Cubitus valgus of elbow