Down Syndrome (trisomy 21)

• result of an extra chromosome 21

• 1:700 children• characteristic facial features,

short stature; heart defects, shorter lifespan… etc.

• has been correlated to the age of the mother but can also be result of nondisjunction of father’s chromosome 21

Down Syndrome

Patau Syndrome (trisomy 13)

• serious eye, brain, circulatory defects as well as cleft palate

• 1:5000• children rarely live more

than a few months

Klinefelter syndrome: XXY

• 47 chromosomes• affects the

sexual/gender specific characteristics

• Usually male sex organs with other female body characteristics

• Normal intelligence

Jacob’s Syndrome

• XYY males• individuals taller than

average, often with below normal intelligence

Trisomy X

• XXX metafemales• 1:1000 live births• healthy and fertile• usually cannot be

distinguished from normal female except by karyotype

Monosomy X – Turner’s Syndrome• Only one sex chromosome – X• 1:5000 • Only monosomy that will

produce viable offspring in humans

• Only have 45 chromosomes• Do not mature sexually during

puberty and are sterile (cannot reproduce)

• Short stature and normal intelligence

• 98% of these fetuses die