Question

Klinefelter's syndrome is generally characterised by:

• A. XO chromosomes in females
• B. XXY chromosomes in males
• C. Trisomy of chromosome 21
• D. Absence of one autosome

Hint:

Remember the common chromosomal disorders:
- Turner's Syndrome: XO (female)
- Klinefelter's Syndrome: XXY (male)
- Down Syndrome: Trisomy 21

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the typical chromosomal characteristic of Klinefelter's syndrome.

Step 3: Detailed Explanation:
Klinefelter's Syndrome: This is a genetic condition that results from the presence of an extra X chromosome in males.
Chromosomal Abnormality: Individuals with Klinefelter's syndrome typically have a karyotype of XXY (instead of the normal XY for males). In some cases, more than two X chromosomes (e.g., XXXY) can be present.
Characteristics: Affected individuals are phenotypically male but often exhibit features such as tall stature, reduced fertility (due to hypogonadism), small testes, gynecomastia (breast development), and sometimes learning disabilities.
Option Analysis:
- (A) XO chromosomes in females: This describes Turner's syndrome (monosomy X).
- (B) XXY chromosomes in males: This accurately describes Klinefelter's syndrome.
- (C) Trisomy of chromosome 21: This describes Down syndrome.
- (D) Absence of one autosome: This would be a lethal condition in most cases.
Therefore, Klinefelter's syndrome is characterized by XXY chromosomes in males.

Step 4: Final Answer:
Klinefelter's syndrome is generally characterised by XXY chromosomes in males.