1. Autosomal and Sex chromosome abnormalities

2. Sex chromosome anomalies
Sex Chromosome Abnormalities
Pattern / Name
Characteristics
Incidence
Treatment
XYY
Male; tall stature; tendency to low IQ, especially verbal
1 in 1,000 male births
No special treatment
XXX (triple X)
Female; normal appearance, menstrual irregularities, learning disorders, mental retardation
1 in 1,000 female births
Special education
XXY (Kleinfelter)
Male, sterility, underdeveloped secondary sex characteristics, small testes, learning disorders
Hormone therapy, special education
XO (Turner)
Female, short stature, webbed neck, impaired spatial abilities, no menstruation, sterility, underdeveloped sex organs, incomplete development of secondary sex characteristics
1 in 3,500 female births
Fragile X
Minor-to-severe mental retardation; symptoms, which are more severe in males, include delayed speech and motor development, speech impairments, and hyperactivity; the most common inherited form of mental retardation
1 in 1,200 male births; 1 in 2,000 female births
Educational and behavioral therapies when needed

3. Sex chromosomes abnormalities
KLINEFLETER SYNDROME
A male with XXY chromosomes
Exhibits some female characteristics
Such as enlarged breasts and
high pitched voice
TURNERS SYNDROME
A female with XO exhibits a short stature, short neck, and broad chest with immature sex organs

4. XYY
If in meiosis II the Y chromosome does not separate and is passed on to a boy the sex chromosomes will be XYY. Boys with this are unusually tall but have normal fertility. Studies have also shown that these men tend to be more violent than a XY male.

5. How does it happen? Non-disjunction can result in
abnormalities in the number of
sex chromosome. Both Klinefelter
and Turners result from nondisjunction
of either the male or female gamete.
The disjunction of the female gametes
can result in a Triple X female

6. Down Syndrome
Down syndrome is a chromosomal abnormality of the 21th chromosome. It is known as Trisomy 21 since nondisjunction of a faulty cell division results in an embryo with three number 21 chromosomes instead of  two. People with down syndrome are usually mentally retarded, shorter, have a larger head and a short life span (usually about 30 years).

7. Down syndrome- Prior to, or at, conception, a pair of number 21 chromosomes, in either the sperm or the egg, fail to separate
Karyotype of down syndrome