Example of Sex Chromosome Disorders -Turner's syndrome, Klinefelter's syndrome, Super males and Super females

Anomalies in Sex chromosomes

Turner's syndrome

• Due to monosomy (2n-1)
• The individual has 2n=45 chromosomes (44+X), instead of 46.
• One in every 3000 females birth is a victim

Turner's syndrome Karyotype

• Such persons are sterile females who have rudimentary ovaries, undeveloped breasts, small uterus, puffy fingers, short stature (less than 5 feet), webbed neck, abnormal intelligence, cardiovascular abnormalities and hearing impairment.

Klinefelter's syndrome

• Is due to trisomy of sex X chromosome
• Individual has47 chromosome (44+XXY).Such persons are sterile males  with undeveloped testes, mental retardation, long limbs and with some female  characteristics such as feminine pitched voice and enlarged breasts (Gynaecomastia)
• One in every 500 male births is the victim of this syndrome.

  Super males

• Such individuals have 47 (44+XYY) chromosomes. Characterized by abnormal height, mental retardation and criminal bent of mind (Jacob’s syndrome or Criminal syndrome)
• Due to the over production of male sex hormones
• Frequency is 1 in 1000.

Super females

• Such individual have 47(44+XXX), 48(44+XXXX), or 49(44+XXXXX), chromosomes.
• These females are characterised by abnormal sexual development and mental retardation.
• The number of barr bodies is less than total number of X-chromosomes.
• The frequency at birth of 44+XXX is 1 in 1500