BIOL 115 Lecture Notes - Lecture 7: Superior Temporal Gyrus, Basal Ganglia, Down Syndrome
Document Summary
Egg has two chromosome 21"s to give, instead of only one. There is a lot of variability in how complete that extra chromosome is, and can affect the symptoms of the person. ~1:750 births, for women of all ages. But also there is a relationship between maternal age and down"s syndrome. Overall, it seems that women over 35 have more incidence of having two 21 chromosomes in their egg cells and therefore are more likely to have children with down"s. For women who are under 35, the actual incidence is like 1:1000s in your early 20"s. Around age 40, its more like 1:few hundreds, and over 45 1:20. Examples of suspected genes on chromosome 21 that are overexpressed in. Sod1 premature aging and decreased function of the immune system. Common abnormality: being short of stature and having sloped shoulders. Very vague, obviously some genetic link with overall cortical development. Different alleles lead to different effects across people.
