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Flashcards in Down syndrome Deck (10):

What is an autosome?

autosome is any chromosome that is not a sex-determining chromosome

NOTE: numerical disorders are more likely in the sex chromosomes.


Etiology of DS?

Approximately 95% caused by nondisjunction or an error in cell division during meiosis resulting in a trisomy of chromosome 21.

A rare seen in offspring of those with a Robertsonian translocation involving long arm of CHR 21q

Inc risk with increase in maternal age


How might maternal age influence risk of down syndrome from trisomy 21?

Inc risk of non disjunction. R/t the aging of the oocyte. Egg (oocytes) are there from birth, higher risk of damage of environmental agents such as drugs, chemicals, and radiation.

Other rare (21q) is not related to maternal age


Clinical presentation of of Down Syndrome?

Appearance: Growth failure, small, square head w/ flat facial profile and depressed nasal bridge. EYES epicanthal folds, and upward slant. EARS: small stubby malformed. MOUTH: open w/ protruding tongue. HEART: Congenital heart disease. INTESTINAL malformations. BONES: acute lymphoblastic leukemia

MENTAL health and emotional problems
mild –moderate intellectual disabilities. Delayed development of language and speech, poor attention and impulse control

Hearing loss/impairment
Congenital heart disease
Delayed development of language and speech, poor attention and impulse control


What are the screening tests for DS?

Blood test to measure maternal serum levels of various markers.
Ultrasonography to measure fetal nuchal transparency.
Collect genetic material via percutaneous umbilical sampling


Incidence in relation to maternal age?

25yrs- 1 in 1250
35yrs- 1 in 400
45yrs- 1 in 100


What is nondisjunction?

The failure of homologous chromosomes or sister chromatids to separate properly during cell division



Treat complications and MNFTS


How many people

35000. 1 in 800 births, most common chr disorder


Connection to another disease