Phase 1 · Understand the Body — Why the disease behaves the way it does.
The One-Line Truth
The whole disease in one chain
Everything on this page exists to explain this line.
Huntington disease is an inherited brain disorder where mutant huntingtin protein kills neurons in the striatum, causing progressive movement problems, dementia, and psychiatric symptoms with no cure.
A Factory With Broken Quality Control
Imagine a car factory where the assembly line supervisor (huntingtin protein) normally checks every part before it gets installed. In Huntington disease, a genetic mistake makes the supervisor's ID badge way too long and malformed, so it gets stuck in machinery and stops working. The defective supervisor can't do quality control anymore, so broken parts pile up inside the factory (toxic protein aggregates in neurons). These broken parts jam the power generators (mitochondria), clog the delivery trucks (axonal transport), and trigger the factory's emergency shutdown system (apoptosis). The assembly line workers (striatal neurons) keep trying to work around the jam, but eventually the accumulating wreckage becomes so bad that critical workers die and the whole factory shuts down (striatal neuron death and symptom emergence). Unlike a factory that can stop production, your brain keeps making the defective supervisor protein for decades until the damage is irreversible.
Huntington Study Group and European Huntington Disease Network guidelines on clinical management of Huntington disease (2020) · American Academy of Neurology practice guideline on genetic testing and counseling for Huntington disease (2019) · National Institute of Neurological Disorders and Stroke (NINDS) Huntington Disease Information Page (2023) · Huntington Disease Society of America nursing and care management recommendations for Huntington disease patients and families (2021) · reviewed 2026-08-29