What is the Difference Between Down Syndrome and Turner Syndrome?

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Down syndrome and Turner syndrome are both chromosomal abnormalities, but they differ in terms of their causes, characteristics, diagnosis, and prognosis. Here are the main differences between the two:

  • Cause: Down syndrome is caused by trisomy of chromosome 21, which means that there is an extra full or partial copy of chromosome 21. Turner syndrome, on the other hand, is caused by a missing or altered X chromosome.
  • Chromosomal Abnormality: In Down syndrome, there is an extra full or partial copy of chromosome 21, while in Turner syndrome, there is a missing or altered X chromosome.
  • Prevalence: Down syndrome affects approximately 1 in 700 babies, and both sexes can be affected. Turner syndrome is less common, affecting only females, and is often not diagnosed until adolescence.
  • Physical Features: Down syndrome is associated with unique facial features, slower overall development, higher incidence of congenital heart abnormalities, decreased or absent fertility, and overall lower life expectancy. Turner syndrome is characterized by a webbed neck, low-set ears, short stature, lack of puberty without hormonal treatment, and heart defects.
  • Mental Disability: Down syndrome is associated with mild to moderate mental disability, while Turner syndrome is associated with infertility.

In summary, Down syndrome is caused by an extra full or partial copy of chromosome 21, while Turner syndrome is caused by a missing or altered X chromosome. Both syndromes have distinct physical features and are associated with different health issues.

Comparative Table: Down Syndrome vs Turner Syndrome

Down syndrome and Turner syndrome are both genetic disorders caused by chromosomal abnormalities. Here is a table summarizing the differences between the two:

Characteristic Down Syndrome Turner Syndrome
Chromosomal Abnormality Extra full or partial chromosome 21 Partial or complete missing of the X chromosome
Affected Individuals Both males and females Only females
Prevalence 1 in 700 babies worldwide 1 in 2500 females
Diagnosis At birth During adolescence
Physical Features Distinct physical features, including wide, flat face, small head, and short neck Short stature, webbed neck, and heart defects
Mental Ability Mild to moderate intellectual disability associated No intellectual disability, but may have learning difficulties
Fertility Both males and females can be affected, but fertility can be decreased in males Infertile without medical assistance
Life Expectancy 50-60 years with specialized care in industrialized countries Normal life expectancy, but may develop health issues such as diabetes and heart problems

In summary, Down syndrome is caused by an extra chromosome 21 and is associated with intellectual disability, while Turner syndrome is caused by a missing or partially missing X chromosome and is associated with infertility and certain physical features.