Question

The correct karyotype description of Patau Syndrome is ____________.

• A. 47, +21
• B. 47, +18
• C. 47, +13
• D. 45, XO

Hint:

For exams, memorize the three most common autosomal trisomies:

\textbf{Trisomy 21}: Down Syndrome
\textbf{Trisomy 18}: Edwards Syndrome
\textbf{Trisomy 13}: Patau Syndrome
Notice that the severity of the syndrome generally increases as the chromosome number decreases (i.e., Trisomy 13 is more severe than Trisomy 21).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The question asks for the specific karyotype associated with Patau Syndrome. A karyotype describes the number and appearance of chromosomes in a cell. Human genetic syndromes are often caused by aneuploidy, an abnormal number of chromosomes.
Step 2: Detailed Explanation:
Let's identify the syndromes associated with each karyotype:

(A) 47, +21: This indicates a total of 47 chromosomes, with an extra copy of chromosome 21. This condition is known as Trisomy 21, or Down Syndrome.
(B) 47, +18: This indicates a total of 47 chromosomes, with an extra copy of chromosome 18. This condition is known as Trisomy 18, or Edwards Syndrome.
(C) 47, +13: This indicates a total of 47 chromosomes, with an extra copy of chromosome 13. This condition is known as Trisomy 13, or Patau Syndrome.
(D) 45, XO: This indicates a total of 45 chromosomes, with only one sex chromosome (an X chromosome) and the other missing. This condition is known as Monosomy X, or Turner Syndrome.
Step 3: Final Answer:
Patau Syndrome is correctly described by the karyotype 47, +13 (Trisomy 13).