Question

Adrianne is five years old and has an extra copy of chromosome 21. She has been diagnosed with the disorder known as

a) Down syndrome
b) Fragile X syndrome
c) Turner syndrome
d) Klinefelter syndrome

Answer 1

Adrianne has Down syndrome, also known as Trisomy 21, which is characterized by the presence of an extra copy of chromosome 21. This disorder leads to intellectual disability, physical deformities, and distinctive facial features.

Step-by-step explanation:

The disorder that Adrianne has, with an extra copy of chromosome 21, is known as Down syndrome (or Trisomy 21).

Down syndrome occurs when a child receives three copies of chromosome 21 instead of the normal two. This additional chromosome disrupts the usual development processes and leads to intellectual disability and physical deformities. Children with Down syndrome often have distinctive facial features and may experience health issues such as heart defects.

In contrast, Fragile X syndrome is caused by a mutation in the FMR1 gene and affects the X chromosome. Turner syndrome is a chromosomal disorder in females where one sex chromosome (X) is missing. Klinefelter syndrome is a condition where males have an extra X chromosome (XXY genotype) and may have underdeveloped sex organs and learning difficulties.