Presentation will depict chromosomal and genetic abnormalities that can be detected both prenatally and during post natal investigations.

1. CHROMOSOMAL AND
GENE-LINKED ABNORMALITIES

2. DOWN SYNDROME

3. Sex-Linked Chromosomal
Abnormalities
• Klinefelter Syndrome – Males - XXY
• Fragile X Syndrome
• Turner Syndrome – Females – XO or part of X
deleted
• XYY Syndrome – Males - XYY

4. KLINEFELTER SYNDROME

5. • Fragile X syndrome – Mental deficiency,
learning disability, short attention span
• Boys with this condition characterized by
cognitive deficits in inhibition, memory and
planning.
• Occurs more frequently in males.

6. TURNER SYNDROME

7. XYY SYNDROME

8. Gene-Linked Abnormalities
• Phenylketonuria (PKU) – the individual cannot
properly metabolize phenylalanine, an amino acid.
• Results from a recessive gene and occurs about once in
every 10,000 to 20,000 live births – primarily in Whites
• Easily detected – can be treated by a diet that prevents
an excess accumulation of phenylalanine.
• Untreated – mental retardation and hyperactivity
• Implications for nature-nurture issue (Heredity-
environment interaction)

9. GENE-LINKED ABNORMALITIES – SICKLE CELL ANEMIA

10. Gene-Linked Abnormalities
• Sickle-cell anemia – impairs the body’s red
blood cells.
• Red blood cells carry oxygen to the body’s
cells and are usually shaped like a disc.
• A recessive gene causes the red blood cell to
become hook-shaped “sickle” that cannot
carry oxygen properly and dies quickly –
Anemia and early death.
• Occurs most in African Americans

11. Gene-Linked Abnormalities
• Cystic fibrosis, diabetes, hemophilia, Huntington’s
disease, spina bifida and Tay- Sachs disease.
• Why these abnormalities occur and how to cure?
– Human Genome Project
• Not all who carry the genetic disorder display the
disorder – other genes or developmental events
sometimes compensate
• Genome analysis – costs and benefits – who
would have access to a person’s genetic profile?
Prospects of job/insurance….