Chromosomal disorders syndromes Syndrome A syndrome is a

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 21 st 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 5 th chromosome • Characteristics – – – Moon shaped face Cat-like cry Small head Wide set eyes Abnormal or low ears Mental retardation

Human Karyotype