CHROMOSOMAL Syndromes
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Transcript of CHROMOSOMAL Syndromes
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
Patau Syndrome
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
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
CHROMOSOMAL SYNDROMES INVOLVING SEX CHROMOSOMES
Klinefelter syndrome
Klinefelter Syndrome
•Caused by: XXY
•Frequency: 1 in 500 to 1 in 1, 000males
•Symptoms: • Male sex organs• Sterile• Breast enlargement• Feminine body characteristics
• Normal intelligence
Jacob’s syndrome
Jacob’s Syndrome
•Caused by: XYY
•Frequency: 1 in 1, 000males
•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, 000females
•Symptoms: • Healthy and fertile females
• Usually cannot be distinguished
Turner’s syndrome
Turner Syndrome
•Caused by: XO- missing
second sex chromosomes
•Frequency: 1 in 5,000females
•Symptoms: • Do not mature sexually
• Sterile• Short stature• Normal intelligence• 98% of fetuses die before birth