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CHROMOSOMAL Syndromes . Human Chromosomes. Down’s Syndrome. Down’s Syndrome. Caused by : extra copy of chromosome 21 (trisomy 21) Frequency : 1 in 700 . Symptoms: short stature heart defects often sterile some degree of intellectual disability Small ears Slanted eyes.
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Down’s Syndrome • Caused by: extra copy of chromosome 21 (trisomy 21) • Frequency: 1 in 700 • Symptoms: • short stature • heart defects • often sterile • some degree of intellectual disability • Small ears • Slanted eyes
Patau Syndrome • Caused by: extra copy of chromosome 13 (trisomy 13) • Frequency: 1 in 5,000 • Symptoms: • Brain, eye, circulatory defects • Cleft palate • Kidney defects • Polydactyl (extra fingers/ toes) • Structural eye defects
Edward’s Syndrome • Caused by: extra copy of chromosome 18 (trisomy 18) • Frequency: 1 in 10,000 • Symptoms: • Short life span (only a few months) • Mental delay • Low birth weight • Defects in heart and other organs • Overlapping fingers
Klinefelter Syndrome • Caused by: XXY • Frequency: 1 in 500 to 1 in 1, 000 males • Symptoms: • Male sex organs • Sterile • Breast enlargement • Feminine body characteristics • Normal intelligence
Jacob’s Syndrome • Caused by: XYY • Frequency: 1 in 1, 000 males • Symptoms: • Taller than average • Often below normal intelligence • It was thought that these men were more aggressive, but this hypothesis has been disproven over time.
Trisomy X Syndrome • Caused by: XXX • Frequency: 1 in 1, 000 females • Symptoms: • Healthy and fertile females • Usually cannot be distinguished
Turner Syndrome • Caused by: XO- missing second sex chromosomes • Frequency: 1 in 5,000 females • Symptoms: • Do not mature sexually • Sterile • Short stature • Normal intelligence • 98% of fetuses die before birth