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