(a) Down syndrome
- Down syndrome is a chromosomal disorder caused by the presence of an extra copy of chromosome 21.
- This results in a total of 47 chromosomes instead of the usual 46.
- Down syndrome is the most common chromosomal disorder, affecting about 1 in 700 births.
(b) Klinefelter syndrome
- Klinefelter syndrome is a chromosomal disorder that occurs in males.
- It is caused by the presence of an extra X chromosome, resulting in a total of 47 chromosomes instead of the usual 46.
- Klinefelter syndrome affects about 1 in 500 males.
The chromosomal abnormalities of Down syndrome and Klinefelter syndrome:
| Condition | Chromosome abnormality | Frequency |
| Down syndrome | Extra copy of chromosome 21 | 1 in 700 births |
| Klinefelter syndrome | Extra X chromosome | 1 in 500 males |
The signs and symptoms of Down syndrome and Klinefelter syndrome
- Intellectual disability
- Short stature
- Flat facial features
- Upward-slanting eyes
- Folds of skin on the inner corners of the eyes
- Small hands and feet
Some common features of Klinefelter syndrome include:
- Infertility
- Small testicles
- Gynecomastia (breast development in males)
- Lean body build
- Reduced facial hair growth
- High-pitched voice
There is no cure for Down syndrome or Klinefelter syndrome. However, there are treatments available to help manage the symptoms. For example, people with Down syndrome may receive special education services to help them reach their full potential. People with Klinefelter syndrome may receive hormone therapy to help with fertility and other symptoms.
People with Down syndrome and Klinefelter syndrome can live long and fulfilling lives. With the right support, they can achieve their goals and contribute to society.