Down Syndrome Flashcards
How does Down Syndrome transmission occur?
Non disjunction
Translocation
Mosaicism
Which mode of transmission is inherited?
Translocation
An extra chromosome 21 is inherited from a parent
Part of chromosome 21 becomes attached (translocated) onto another chromosome before or at conception
Which mode of transmission is the most common?
Nondisjunction
***Responsible for the majority of cases (95%) and is not inherited
occurs during cell division and the embryo ends up with 47 chromosomes, with 3 copies of number 21
T/F: Down Syndrome occurs more frequently in males than females and across all races and ethnic groups?
TRUE
Which genetic test during pregnancy has high sensitivity and specificity for chromosomal disorders and has no risk to the fetus?
NIPT
Non invasive prenatal testing
**maternal blood can be analyzed for pieces of cell-free fetal DNA. The amount of fetal DNA from various chromosomes can provide information about fetal genetics.
done at 10 or more weeks gestation.
Which genetic test is performed in the second trimester, includes analysis of chemicals and hormones to assess risk of 3 types of trisomy. It also examines the alpha fetoprotein, which can indicate whether the neural tube has properly fused?
Quad Screen
- ** done at 15-22 weeks gestation
- **detecs neural tube defects, trisomies 13, 18 and 21
When is maternal serum screening done and what can it detect?
it is done between 10-14 weeks
It can detect an increased risk for trisomies 13, 18 and 21
When is nuchal translucency done and what does it detect?
Done 10-14 weeks gestation (ideally 11 weeks gestation)
- ultrasound evaluation of the fetal nuchal fold
- *it can detect fetal anomalies and aneuploidy
Produced by growing fetus and found in amniotic fluid, fetal blood, and maternal blood
Alpha fetoprotein (AFP)
made by placenta and fetal liver
Estriol
made by placenta
HCG:
What substances does the Quad Screen look for?
Estriol
AFP (alpha fetoprotein)
Inhibin A
hCG
What are the two invasive tests that can be performed to check for genetic anomalies?
Chorionic villus samping (CVS): done after 10 weeks
Amniocentesis: performed around 15 weeks
What are the three most common physical characteristics seen with Down Syndrome?
hypotonia
epicanthal folds
transverse palmar creases
What is the most common cardiac defect seen with Down Syndrome?
Atrioventricular septal defect (ASD)
Most Down Syndrome individuals have what form of intellectual developmental disability? (mild, moderate, severe or profound)
Most have MODERATE intellectual developmental disabilities
** IQ of 40 to 55
Velocity of linear growth reduced, especially between ______and _________ months and again in ____________.
between 6 and 24 months
adolescence
What age does the tendency to being overweight begin
Starts around 2 years of age
Results from “loose joint” or laxity between C1 and C2
and has the potential to cause spinal compression. Early signs and symptoms include head tilt, torticollis or deterioration in gait?
Atlantoaxial Instability
How do you screen for atlantoaxial instability and when is this screening recommended?
Recommend one set of cervical spine films between 3 and 5 years of age
Also participants in special Olympics need to be screened for this periodically
At every age, children with Down syndrome are above _____ for weight?
85%
Which defect interferes with gross motor development and causes laxity in the ligament structure?
Hypotonia
Can females with Down Syndrome get pregnant?
YES
What screening is performed at birth on child with Down syndrome?
EKG
cardiac ultrasound
