Benign hereditary chorea is a rare disorder that affects movement. The condition starts in infancy or childhood. Although it affects movement, it can also cause additional problems in other organs, such as the lungs.
Benign hereditary chorea causes symptoms early in life, during childhood or infancy. Chorea is a condition that causes unpredictable, involuntary movements.
Both children and infants with the condition may develop additional problems, such as recurrent lung infections or thyroid disease. In fact, only
The article below covers the symptoms, causes, and treatments of benign hereditary chorea.
BHC is a rare genetic disorder that affects movement.
A person usually has the condition from birth, and the symptoms may start in infancy. In other cases, symptoms present in childhood. However, the onset of symptoms typically occurs in early childhood, with a median age of
The condition can cause problems with muscle tone and walking. Although doctors classify BHC as a movement disorder, it can affect other areas of the body, such as the thyroid and the lungs. Behavior and learning difficulties can also occur.
Learn more about chorea disease.
How rare is BHC?
Because the condition is so rare, exact data on the prevalence of the condition remain limited. Researchers estimate that BHC occurs in about
Symptoms of BHC may vary in severity, but most people with the condition develop atypical walking patterns and jerky movements. Their movements are irregular and may appear as twitching, twisting, or fidgeting.
Additional symptoms that may start in infancy
- low muscle tone, or hypotonia
- involuntary movements, or dystonia
- frequent lung infections
- respiratory distress
In children, symptoms that may also appear include:
- delayed walking
- body movement tics
- vocal tics
- upper limb dystonia, or muscle spasms
- behavior problems
Although children with the condition tend to have typical intelligence, they may have some learning challenges. Some also develop problems with speech.
About 40% of children also develop dysarthria, a speech disorder that occurs due to muscle weakness. This may cause stuttering and slurred speech.
Thyroid problems may also occur, especially hypothyroidism, which involves low thyroid hormone levels.
BHC occurs due to gene variations, which involve changes to the DNA of a cell.
Researchers have identified genetic changes in the NKX2.1 gene — also known as the TITF1 gene — in people with the condition. A 2017 study identified over 30 different gene mutations in NKX2.1 for BHC.
Gene variations can occur for various reasons, such as errors in cell division and exposure to viruses. It is unclear why gene variations occur with BHC.
The condition can pass down through families in an autosomal dominant pattern. This means a person only needs one copy of the gene variant to have the disease. The biological child of someone with BHC has a 50% likelihood of acquiring the gene variant and disease.
However, in other cases, the condition can occur with no family history of the disease.
Sometimes, doctors recommend certain diagnostic tests to rule out other conditions that cause similar symptoms. Because the disease is rare, a delay in diagnosis can occur in children.
Currently, there are
Usually, healthcare professionals individualize treatment for each child according to the severity of their symptoms.
Possible treatment options include the following.
Doctors may prescribe different medications, including levodopa, which is a medication for treating Parkinson’s disease. It may help improve some motor symptoms.
The brand name for levodopa, when pharmaceutical companies mix it with the drug carbidopa, is Sinemet.
Physical therapy may help children improve muscle tone, movement control, and walking.
Learn more about physical therapy.
Speech therapists can help children improve issues relating to weakened muscles involved in speech. This may reduce stuttering and slurred speech.
Treatment also includes medication to address low thyroid levels and lung infections in children who develop these associated conditions.
The outlook for people with BHC varies.
The motor symptoms do not
Thyroid and lung involvement occurs frequently — the disease causes thyroid symptoms in about
People with the gene mutation that causes BHC may also have an increased risk of cancer. Lung cancer is the most frequently associated cancer with the NKX2.1 mutation. Frequent respiratory infections or asthma may precede a diagnosis of lung cancer.
It can be challenging to find support for rare diseases, including BHC. A healthcare professional may have information on resources and general information about the condition.
People can also find additional resources and support from the following organizations:
Benign hereditary chorea is an uncommon inherited movement disease. Typically, its symptoms start in infancy or early childhood.
Symptoms include muscle tone issues, tics, and delayed walking. Some children may also develop lung and thyroid problems.
Although currently there is no cure, treatment may help decrease symptoms, and the options may include medication and physical and speech therapy. The condition may remain stable and improve by early adulthood.