How Is Huntington’s Disease Diagnosed?

Huntington’s disease is diagnosed based on genetic testing and an evaluation of clinical symptoms. Other diagnostic studies that may help in evaluating disease progression include brain imaging and disease staging rating scales.

Clinical Assessment 

If you have symptoms of Huntington’s disease or any neurological symptoms, it’s crucial for you to see a healthcare provider. 

A clinical diagnosis of Huntington’s disease is based on:

• A review of your symptoms, the timing, and the progression
• A physical examination, which will include assessment of your reflexes, walking, muscle tone, coordination, muscle strength, and speech
• Consideration of other medical conditions that could be causing your symptoms

It’s possible for a person to be the first in their family to experience Huntington’s disease, especially if parents or grandparents died before the symptoms developed, or without an accurate diagnosis.

Genetic Testing

A genetic blood test can identify whether you have the gene that causes Huntington’s disease. If you have inherited the gene that causes this disease, you will develop Huntington’s disease, and if you do not have the gene that causes the disease, you will not develop the condition.

Huntington’s disease usually begins to cause symptoms in middle age. There is a form of Huntington’s disease defined as juvenile onset, where people begin to experience symptoms earlier. 

Individuals who have a known family history of Huntington’s disease may opt to have a genetic test at any age. If you have a known family history of Huntington’s disease, the decision to have a blood test requires a lot of thought, because:

• If you have the gene, each child you have has a 50% chance of inheriting the gene.
• Knowing that you will develop the disease can lead to depression.
• You might make major life decisions based on the outcome of the test.
• Huntington’s disease usually causes early death.
• Siblings may have strained relationships if some siblings inherit the gene, and others do not.

You could consider speaking with a genetic counselor as you make your decision about getting tested.

Disease Stage 

If you’ve been diagnosed with Huntington’s disease, your medical team may track your condition using measures such as:

• Huntington’s Disease Integrated Staging System (HD-ISS)
• Total Functional Capacity (TFC) scale
• Adult Functional Adaptive Behavior (AFAB) scale

These scales provide consistency for your health care team to use to define your Huntington’s disease progression, with benchmarks for cognitive and physical abilities.

Brain Imaging

Brain imaging studies, including magnetic resonance imaging (MRI) and positron emission tomography (PET), can identify patterns consistent with Huntington’s disease.

Imaging can be used as a supplement to your diagnostic process by identifying atrophy (shrinking) and damage to brain cells in different areas of the brain.

Surveillance for Complications 

If you’re living with Huntington’s disease, you need ongoing medical care so complications can be detected any early stage.

Monitoring may include:

• Periodic assessment of your swallowing abilities
• Medical attention if you develop a fever or any signs of an infection
• Screening for symptoms of depression
• Testing of your cognitive abilities (thinking and problem-solving skills)
• Screening for thought disorders, such as hallucinations or delusions

Your medical team will look for signs of illness, worsening disability, and disease progression, so you can receive adequate treatment to reduce the risk of life-threatening health complications.

Emerging Tests 

Several emerging tests are being examined in research settings to develop markers for Huntington’s disease, including blood protein markers and imaging tools. These tests may improve the staging process and help develop new treatments and evaluate treatment effectiveness.