It is thought that genetic errors are responsible for more than 4000 hereditary diseases.

• A. True
• B. False
• C. Not known
• D. Not mentioned

Answer: (A)

Genetic errors underlie a large majority of hereditary diseases. As our understanding of the genome has grown, researchers have identified thousands of conditions that are caused by mutations in one or more genes, and catalogs of these disorders routinely cite numbers in the thousands. The estimate that more than 4000 hereditary diseases are linked to gene errors reflects this extensive cataloging. While some inherited conditions involve multiple genes or chromosomal changes and others arise from de novo mutations, the essential idea is that a vast number of hereditary diseases have a genetic basis, which is why this statement is considered true.