Chromosomal disorders (syndromes)

Syndrome A syndrome is a group of symptoms with a single underlying cause Several syndromes result from nondisjunction which is the failure of chromosomes to separate properly during meiosis The resulting egg or sperm will carry an unusual number of chromosomes

Down’s Syndrome Trisomy 21 (nondisjunction of the 21st chromosome) = 47 chromosomes overall Characteristics Short stature Mentally challenged Deformed hearts Abnormal eyelids Large tongues

Klinefelter’s Syndrome Nondisjunction of sex chromosomes ending up with XXY Characteristics Sexually immature Males develop large breasts High pitched voice Low intelligence Look stretched Y chromosome = male

Turner’s Syndrome Nondisjunction of sex chromosomes resulting in X (45 chromosomes) Characteristics Shorter, stockier girls Large necks Sexually immature

Super Male Syndrome Nondisjunction of sex chromosomes ending up with XYY Characteristics More aggressive Tall Acne

Cri-du-chat syndrome Results from missing a part of the 5th chromosome Characteristics Moon shaped face Cat-like cry Small head Wide set eyes Abnormal or low ears Mental retardation

Human Karyotype