Today, We Know More About Huntington's Disease Than Ever Before

Huntington's disease (HD) is a genetic, neurodegenerative disease characterized by cognitive and motor decline and behavioral symptoms. HD impacts families across generations, with each child of a parent with HD having a 50/50 chance of developing the disease. 1,2

The more we learn about the mutant huntingtin (mHTT) protein responsible for causing HD, the closer we get to unlocking the mysteries of this condition.

Watch to learn more about HD

Huntington's Disease is Characterized by a Triad of Symptoms

Since patients experience these symptoms in their own unique way, HD can often be challenging to diagnose.

*This is not a comprehensive list of HD symptoms.

Huntington’s Disease Progression Can Be Described in 3 Phases

Onset of HD typically occurs when an individual is between 30 and 50 years of age. HD can progress over a period of 15 to 20 years, as cognitive and motor symptoms increase and functional capacity declines. HD phasing terminology does continue to evolve; however, the disease generally progresses through these phases. 2,9,10

The significance of expanded CAG trinucleotide repeats

Researchers identified that the number of cytosine-adenine-guanine (CAG) trinucleotide repeat expansions in the huntingtin gene (HTT ) has been shown to correlate with the age of disease onset. 1,2

 

The number of CAG trinucleotide repeats is key to pathogenesis.

Normal: ≤26 CAG repeats

  • Risk of HD in patient: No
  • Risk of HD in next generation: No

High Normal: 27 – 35 CAG repeats

  • Risk of HD in patient: No
  • Risk of HD in next generation: Possible

Reduced Penetrance: 36 – 39 expanded CAG repeats

  • Risk of HD in patient: Possible
  • Risk of HD in next generation: Yes

Full Penetrance: ≥40 expanded CAG repeats

  • Risk of HD in patient: Definite HD
  • Risk of HD in next generation: Yes

A blood test can be performed to determine the CAG repeat length. 1