Karyotypes
1. What is a karyotype? a. Picture of the 23 pairs of chromosomes
2. How are the chromosomes arranged? a. Size b. Banding c. Position of centromere
3. Types of chromosomes a. Autonomies: a. 1 st 22 pairs b. Non sex chromosomes b. Sex chromosomes a. 23 rd pair b. XX – female c. XY - male
4. Reasons for Karyotypes a. Detection of chromosomal disorders a. Performed by amniocentesis b. Including: a. Down’s syndrome a. Trisomy 21 b. Klinefelter’s syndrome a. Trisomy 23 c. Turner’s syndrome a. Monosomy 23
Normal male
Down’s Syndrome
Trisomy 21 Mental retardation Stunted growth Small chin Weaker immune system Eyelid crease Smaller palate
Turner’s Syndrome
Turner’s syndrome Occurs in females Only inherit one x chromosome Sterile = unable to reproduce Broad chest
Klinefelter’s syndrome Occurs in males Extra x chromosomes (XXY or XXXY) Infertile Low testosterone Increased breast tissue
Name that disorder
Patau Syndrome Trisomy 13 Cleft palate Mental retardation Polydactyl Seizures Skeletal abnormalities Decreased muscle tone