Down Syndrome Flashcards
1
Q
symptoms or characteristics
A
low muscle tone flat facial features, small nose upward slant of eyes small, abnormally shaped ears hyper flexibility enlarged tongue short neck small hands and feet shorter in height line across palm of hand tiny white spots on eyes iris
2
Q
what is trisomy 21 down syndrome
A
- not inherited
- caused by abnormal cell division during development of sperm or egg
- child has 3 copies of chromosome 21 instead of 2
3
Q
percentage of trisomy 21 down syndrome
A
95%
4
Q
summary of down syndrome
A
chromosomal condition associated with intellectual disability, a characteristic facial appearance and weak muscle tone in infants
5
Q
percentage of translocation down syndrome
A
3%
6
Q
what is translocation down syndrome
A
- inherited by unaffected parent (carrier)
- part of chromosome 21 becomes attached (translocated) onto another chromosome before or at conception
- results in 2 usual copies of chromosome 21 as well as additional material from chromosome 21 attached to the translocated chromosome
7
Q
percentage of mosaic down syndrome
A
2%
8
Q
risk factors
A
- advancing maternal age (over 35) - chances increase because older eggs have a greater risk of improper chromosome division
- other children with down syndrome
- carries of translocation for down syndrome
10
Q
what is mosaic down syndrome
A
- not inherited
- caused by abnormal cell division after fertilisation
- results in some cells having 3 copies of chromosome 21 and some having the usual 2 copies
