Down’s Syndrome Flashcards
What does aneuploidy mean?
It means an abnormal number of chromosomes
What are the chances of trisomy 21 in live births?
1:1500 in SA
What are the 3 types of Down’s syndrome?
- Non disjunction (95%)
- Translocation (4%)
- Mosaicism (1-2%)
What is non-dysjunction about?
All cells in the body are affected
-either one of the gametes(egg or sperm have 3 chromosomes instead of 2)
What is translocation about?
- The chromosomes at chromosome 21 translocates with the long arm of another chromosome(usually 14)
- increased risk of affecting more children
What is mosaicism about?
Some of the cells in the body are affected and some are not
What are the facial clinical features of a child with Down’s Syndrome?
- Upslanting eyes
- Epicanthic folds
- Flat nasal bridge
- Large protruding tongue
- Small teeth with gaps in between
- Low set ears
- Brachycepahly (flat head)
- Micrognathia
What are the clinical signs we can expect on the child’s hands?
- Brachydactyly-short fingers
- Hypoplastic nails(absent or really small nails)
- Clinodactyly-curvature of the fifth digit inwards)
- Single palmar crease(Simean palmar crease)
What can we expect to see on the feet?
Sandal gap
What eye abnormalities can we expect in Downs patients?
- Strabismus
- Congenital cataract
- Glaucoma
- Brush field spots in the iris(grey/brown)
What congenital heart defects are they prone to getting?
- AVSD
2. ASD
What percentage have the chance of getting hypothyroidism?
30%
What gastrointestinal clinical symptoms can they present with?
- Duodenal atresia
- Celiac disaese
- Malabsorption
What neurological problems do they present with?
- Increased risk of epilepsy
2. Low IQ
How would you manage this child?
- Monitor growth and development and involve speech therapists, physios and social workers as needed especially to help the family adapt
- Surgery as indicated for example for the congenital heart defects
- Genetic counselling
