A fatal central nervous system disorder caused by a copy number variation-more than 35 repetitions of a particular set of three base pairs-is _____.

Question

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Huntington disease is caused by a genetic mutation that leads to an excessive number of repeats of a specific three-base sequence within the Huntingtin gene. This leads to the production of a toxic protein that damages neurons in the brain, causing the symptoms of Huntington disease. Down syndrome is caused by an extra copy of chromosome 21, nearsightedness is a vision problem caused by the shape of the eye, and fragile X syndrome is caused by a mutation in the FMR1 gene.

A Fatal Central Nervous System Disorder Caused by a Copy