Downs Syndrome Flashcards
What is it ?
A genetic condition in which there is an extra chromosome on chromosome 21: Trisomy 21
Incidence in pregnancies
1 in 1000
What is the incidence in pregnancies in women over 30 years of age ?
1 in 300 pregnancies
What are 5 main features of Down’s syndrome ?
- Look different to compared to other babies, 2. Are slower to develop 3. Some degree of a learning disability, 4. May develop or be born with heart or bowel problems 5. Likely to develop early onset dementia: Alzheimer’s disease
What screening test is offered to all pregnant women ?
Combined Test
What does the combined test involved ?
USS scan, nuchal translucency (thickened: fat at the back of the head is increased) and serum biomarkers + (PAPP-A low; B-hcg high) + maternal age (increasing) and previous obstetric Hx
If booking is done later than when it’s suppose to be what is done instead ?
Triple or quadruple test between 15+0 and 20+6
What does the quadruple test involve ? (4)
AFP: alpha fetoprotein (low),
Oestradiol (low); inhibin and b-Hcg (high)
What are the group of risk factors for Down’s syndrome ? (3)
Hx RFs, rare RFs and USS
What are the Hx RFs ? (2)
- High maternal age and 2.previous obstetric Hx: previous DS pregnancy/FH
What is the rare RF ? (1)
Balanced placental translocation
What is the mnemonic for the USSs RFs ?
SATS
What are the USS RFs ?
- Some structural abnormalities,
- Absent/shortened nasal bone
- Tricuspid regurgitation and 4. Severe growth restriction
What are the definitive tests used in diagnosing Down’s syndrome ?
Chorionic villus sampling and amniocentesis
The definitive tests used for Down’s syndrome are also used for others, what are these ?
Sickle cell anaemia
