**Core Concept**
DNA analysis of chorionic villus/amniocentesis is a prenatal diagnostic technique used to detect genetic disorders in the fetus. This test involves analyzing fetal cells obtained from chorionic villus sampling or amniocentesis to identify chromosomal abnormalities, single-gene disorders, and other genetic conditions.

**Why the Correct Answer is Right**
Tay-Sach's disease is caused by a deficiency of the enzyme hexosaminidase A (Hex-A), which is due to mutations in the HEXA gene. This enzyme deficiency leads to the accumulation of GM2 ganglioside in neurons, causing neurodegeneration and the characteristic symptoms of Tay-Sach's disease. However, the HEXA gene is located on chromosome 15, and DNA analysis of chorionic villus/amniocentesis typically detects chromosomal abnormalities or single-gene disorders caused by mutations in genes that are linked to the sex chromosomes (X or Y) or to autosomal chromosomes (1-22) that are easily detectable through the aforementioned tests. As a result, Tay-Sach's disease is not likely to be detected through chorionic villus/amniocentesis.

**Why Each Wrong Option is Incorrect**
**Option B:** Hemophilia A is caused by mutations in the F8 gene on the X chromosome, which can be detected through chorionic villus/amniocentesis. This condition is an X-linked recessive disorder, making it a suitable candidate for prenatal diagnosis.
**Option C:** Sickle cell disease is caused by a mutation in the HBB gene on chromosome 11, which can be detected through chorionic villus/amniocentesis. This condition is an autosomal recessive disorder, making it a suitable candidate for prenatal diagnosis.
**Option D:** Duchenne muscular dystrophy is caused by mutations in the DMD gene on the X chromosome, which can be detected through chorionic villus/amniocentesis. This condition is an X-linked recessive disorder, making it a suitable candidate for prenatal diagnosis.

**Clinical Pearl / High-Yield Fact**
It is essential to note that chorionic villus/amniocentesis is a diagnostic test that can detect chromosomal abnormalities and single-gene disorders caused by mutations in genes linked to the sex chromosomes or to autosomal chromosomes. However, it may not detect conditions caused by mutations in genes that are not easily detectable through these tests, such as Tay-Sach's disease.

**✓ Correct Answer: A. Tay-Sach's disease**