1983 discovery of Huntington’s gene mutation opened door to 5,000+ disease-linked genes

A breakthrough in a Harvard lab 43 years ago changed how we understand disease. In 1983, geneticists James Gusella and Nancy Wexler reported in a landmark paper that Huntington’s disease — a fatal condition where brain cells progressively decay — was caused by a mutation on chromosome 4. It was the first time a single gene had been directly implicated in a human disease.

Since then, that discovery has snowballed. Scientists have now identified about 5,000 genes whose mutations can increase susceptibility to a wide range of afflictions, from obesity to schizophrenia and bipolar disorder.

The 1983 paper didn’t just explain Huntington’s. It proved that genetics could unlock the “why” behind illness, paving the way for modern genomics, targeted therapies, and early risk screening.

For medicine today, it’s the foundation. One gene, one disease — and now thousands of genes helping us understand thousands of conditions.