Frameshift mutations are commonly seen in which of the following conditions?

Frameshift mutations are characterized by the insertion or deletion of nucleotides in a DNA sequence that alters the reading frame of the genetic code. This type of mutation can lead to the production of a completely different protein, often resulting in significant functional consequences.

In Duchenne muscular dystrophy, frameshift mutations are frequently observed in the dystrophin gene. These mutations result in abnormal or truncated dystrophin protein, leading to the severe muscle weakness characteristic of the disease.

Cystic fibrosis is primarily caused by mutations in the CFTR gene, many of which can also be frameshift mutations. These alterations can disrupt the normal function of the CFTR protein, which is critical for chloride ion transport across epithelial membranes, leading to the accumulation of thick mucus in various organs.

Tay-Sachs disease is typically associated with a specific type of mutation in the HEXA gene, which encodes an enzyme involved in ganglioside metabolism. While the classic mutation is a point mutation, frameshift mutations can also occur in this gene, affecting the enzymatic activity necessary for proper lipid metabolism.

Given that frameshift mutations can indeed be associated with Duchenne muscular dystrophy, cystic fibrosis, and Tay-Sachs disease, the correct answer encompasses all of these conditions.