Diseases mimicking Huntington's (HD) include other trinucleotide repeat disorders like spinocerebellar ataxias (SCA1, SCA3), neuroacanthocytosis syndromes (chorea-acanthocytosis, McLeod syndrome), brain iron accumulation disorders (PKAN, neuroferritinopathy), Wilson's disease, and some mitochondrial or autoimmune conditions, all presenting with chorea, dementia, or psychiatric changes, requiring careful genetic/clinical differentiation.
The presence of psychotic symptoms in premanifest Huntington's disease can be particularly misleading because, together with progressive apathy and cognitive impairment (mistaken for negative symptoms), they may lead to an erroneous diagnosis of schizophrenia.
The Huntington genetic test is a blood test to check for the genetic disease. If you have a family member who has Huntington disease, their blood usually is tested first to identify the changed gene that might run in your family. Then you give a blood sample, which is screened for the gene change.
Huntington's disease is clinically characterized by a triad of motor, cognitive and psychiatric symptoms. Motor features include: impairment of involuntary (chorea) and voluntary movements; reduced manual dexterity, slurred speech, swallowing difficulties, balance problems and falls.
Others include mutations in C9orf72, spinocerebellar ataxias type 1 and 3, neuroacanthocytosis, dentatorubral-pallidoluysian atrophy (DRPLA), brain iron accumulation disorders, Wilson's disease, benign hereditary chorea, Friedreich's ataxia and mitochondrial diseases.
The neuropsychiatric symptoms of Huntington's disease often mimics those of bipolar disorder, leading to frequent misdiagnosis. A comprehensive clinical evaluation that includes genetic testing, neuroimaging, and consideration of both neuropsychiatric and motor symptoms is crucial for accurate diagnosis.
Degenerative nerve diseases include:
Blood tests, specifically genetic testing, can determine the likelihood of developing Huntington's disease. Additional procedures that may help in the neurological workup may include: Computed tomography (CT) scan. Magnetic resonance imaging (MRI) scan.
Huntington's disease is an inherited condition associated with uncontrolled movements, psychiatric disturbances, and cognitive decline. ALS, also known as Lou Gehrig's disease, is associated with muscle weakness and (eventually) complete paralysis. The vast majority of ALS cases are not inherited.
The most effective and accurate method of testing for HD—called the direct genetic test—counts the number of CAG repeats in the HD gene, using DNA taken from a blood sample. The presence of 36 or more repeats supports a diagnosis of HD.
The most common signs of Huntington's disease include:
Cognitive changes, including difficulty with focus, memory and decision-making. Slower processing of information. Trouble organizing or completing tasks. Mood swings or irritability.
HD affects the whole brain, but certain areas are more vulnerable than others. Pictured above in blue is the striatum – an area deep in the brain that plays a key role in movement, mood, and behavior control. The striatum is the part of the brain that is most affected by HD.
Brain-imaging and function tests
These images may reveal changes in the brain in areas affected by Huntington's disease. These changes may not show up early in the course of the disease. These tests also can be used to rule out other conditions that may be causing symptoms.
Parkinson's disease and Huntington's disease both impact movement and daily life, but they are distinct conditions with different causes and symptoms. Parkinson's disease typically leads to resting tremors and slow movement, while Huntington's disease results in jerky, uncontrolled movements.
Analytic validity was high (sensitivity: 99.5%, 95% confidence interval: 97.1–99.9%; specificity: 99.2%, 95% confidence interval: 97.1–99.9%). Repeat length errors occurred in 2.6% (95% confidence interval: 1.8–3.8%) of 1,060 allelic challenges, with most being minor or from a single participant.
Common complications include problems with eating and swallowing (dysphagia), particularly as the disease progresses. The loss of muscle control and coordination means that spilling food from the mouth and choking are possible.
Early signs of ALS often involve painless muscle weakness, such as tripping or dropping things, along with muscle twitching (fasciculations), cramping, and stiffness (spasticity), commonly starting in limbs but sometimes affecting speech (slurring) or swallowing (choking). Other early indicators include significant fatigue, poor balance, or even uncontrollable laughing/crying (pseudobulbar affect). These symptoms usually begin subtly in one area and spread, affecting daily activities before becoming severe.
Early symptoms of Huntington's disease include:
In Australia, ALS (Amyotrophic Lateral Sclerosis) is most commonly known as Motor Neurone Disease (MND), though the terms are often used interchangeably, with MND being the preferred local term for this rapidly progressive neurological condition affecting nerve cells that control muscles. So, you'll see it called MND, but it's the same disease as ALS.
Genetic Testing
Polymerase chain reaction (PCR) testing and size analysis for an expanded number of cytosine-adenine-guanine (CAG) trinucleotide repeats in the HTT gene may be performed for both symptomatic individuals and asymptomatic individuals with a family history of HD.
Of all the psychiatric manifestations of HD, the executive dysfunction syndrome of HD, while difficult to define and characterize, may be the most common. Individuals with this syndrome may become apathetic, irritable, disinhibited, impulsive, obsessional, and perseverative.
The gold standard for evaluation is genetic testing, which is targeted testing of the CAG repeat size. A patient with 26 or fewer repeats is not associated with the Huntington disease phenotype.
PD patients are six times more likely to develop dementia than the general population. Parkinson's disease is the second most common neurological disease in Australia after dementia. More than 150,000 Australians are living with Parkinson's disease, and 50 more are diagnosed every day.
Neurodegenerative disorders gradually damage nerve cells, leading to problems with movement, memory, or behavior. Common symptoms include memory loss, tremors, difficulty walking, mood changes, and personality shifts.
Parkinson's disease is the fastest growing neurodegenerative disease in the world, and the second most common after Alzheimer's disease. There are an estimated 1 million people in the U.S. living with PD and more than 10 million people worldwide. Every 6 minutes, someone is diagnosed with PD.