Chromosomal Disorders - Practice Questions & MCQ

Down’s Syndrome:

• It was described by J Langdon Down in 1866. 
• It occurs due to the additional copy of chromosome number 21 or trisomy of chromosome 21 in humans and also seen in chimpanzees and other related primates.
• Symptoms:
  • Individuals are short-statured with small, round head and furrowed tongue.
  • Partially open mouth, the palm is broad with characteristic palm crease.
  • Slow mental development.

Klinefelter’s Syndrome:

• It occurs due to the presence of an additional copy of X-chromosome resulting in the karyotype 45 + XXY which results into 47 chromosomes.
• Symptoms:
  • Individuals have masculine development but feminine characters like the development of breasts, (gynecomastia) etc.
  • Poor bread growth and often sterile and feminine pitched voice.

Turner’s Syndrome:

• It is a disorder caused due to the absence of one of the X-chromosome, i.e., 45 with XO.
• Symptoms:
  • Affected females are sterile as ovaries are rudimentary.
  • Lack of secondary sexual characters and poor breast development. Short stature, small uterus, puffy fingers and webbed neck.