Huntington disease-like syndrome due to C9ORF72 expansions

Huntington disease-like syndrome due to C9ORF72 expansions is a rare neurological condition that closely resembles Huntington disease but is caused by a different genetic change. Instead of the typical Huntington disease gene mutation, this condition is caused by an abnormal repeat expansion in the C9ORF72 gene, which is more commonly associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). People with this condition may develop involuntary movements called chorea, personality and behavioral changes, cognitive decline, and psychiatric symptoms — all features that look very similar to classic Huntington disease. The condition typically appears in adulthood and tends to get worse over time. Because this syndrome mimics Huntington disease, patients are often initially suspected of having Huntington disease, but standard genetic testing for the HTT gene comes back negative. It is only when broader genetic testing is performed, specifically looking at the C9ORF72 gene, that the correct diagnosis is made. This is sometimes referred to as a Huntington disease phenocopy or Huntington disease-like (HDL) syndrome. There is currently no cure or disease-modifying treatment for this condition. Management focuses on relieving symptoms such as movement problems, psychiatric symptoms, and cognitive difficulties. A team of specialists including neurologists, psychiatrists, and genetic counselors typically provides care. Research into therapies targeting C9ORF72 repeat expansions is ongoing, offering hope for future treatments.

Bring these to your next appointment

• Q1.How certain is the diagnosis, and should other family members be tested for the C9ORF72 expansion?,What symptoms should I watch for that might indicate the disease is progressing?,Are there any clinical trials or experimental treatments I might be eligible for?,What medications can help manage my movement or psychiatric symptoms?,Should I also be monitored for signs of motor neuron disease (ALS)?,What support services are available, including physical therapy, speech therapy, and counseling?,How should I plan for future care needs as the disease progresses?

Common questions about Huntington disease-like syndrome due to C9ORF72 expansions

Related conditions

Other rare diseases commonly researched alongside Huntington disease-like syndrome due to C9ORF72 expansions.

• Frontotemporal dementia→
• Huntington disease→