Diagnosis and management of rare disorders: The example of Huntington’s disease

This analysis was developed in partnership between Anne Graul, Senior Content Manager, and Shyama Ghosh, Science Editor, Incidence and Prevalence Database, both of Clarivate Analytics. 


Rare Disease Day takes place on the last day of February each year aimed at raising awareness about rare diseases and their impact on patients’ lives. There are more than 7,000 existing rare diseases and the lack of scientific knowledge and quality information on these diseases often results in delayed diagnosis and treatment. Here is an excerpt from a paper from Clarivate Analytics which profiles all aspects of one of them:

Huntington’s disease is a fatal, rare genetic disorder that causes the progressive breakdown of nerve cells in the brain. Symptoms usually appear between the ages of 30 and 50, and worsen over a 10- to 25-year period, during which the affected person gradually becomes totally incapacitated and unable to communicate. In patients with the juvenile-onset form of the disease, symptoms become evident before age 20 and progression is more rapid, with duration of disease in the range of eight to 10 years.

Huntington’s disease affects both sexes and all races and ethnic groups around the world. Within a family, multiple generations may inherit the disease. Every child of a parent with this disease has a 50/50 chance of inheriting the mutated gene that causes the disorder (autosomal dominant trait). With a mean duration of illness longer than 17 years, this is a lifelong disease for both the individual and the family.

Neuropsychiatric symptoms, cognitive dysfunction and worsening motor symptoms are the hallmark of this degenerative disease which ultimately leads to complete care dependency and death.

Until the emergence of symptoms, affected individuals appear to be completely normal and have no detectable clinical signs. Initial symptoms of Huntington’s disease are subtle and may include forgetfulness, clumsiness, slight personality alterations and/or the gradual emergence of brief, random “fidgeting” movements of the fingers and toes. This prodromal phase may precede emergence of full-blown Huntington’s disease by several years.

In patients with more advanced disease, the triad of neurobehavioral, cognitive and motor symptoms becomes more noticeable and has a significant impact on quality of life for both patients and their families.



Current treatment of a patient with Huntington’s disease requires a multidisciplinary approach incorporating aspects of symptomatic and supportive medical care; counseling and psychosocial support; physical, speech and occupational therapy; nutrition approaches; and more.

The potential of various classes of experimental therapies are being examined for Huntington’s disease,  including dopamine depletors and stabilizers, drugs acting on glutamate receptors, histone deacetylase inhibitors, phosphodiesterase inhibitors, drugs targeting mitochondrial dysfunction, antioxidants, drugs acting on cannabinoid receptors, apoptosis inhibitors, tissue transglutaminase inhibitors, therapies targeting mutant huntingtin protein aggregation, therapies targeting huntingtin expression and cell therapy.

This 2017 article in BioWorld, the biopharma news service from Clarivate Analytics, provides insight into the challenges for drug developers seeking new therapies for the disease, Victories in Huntington’s disease few and far between, but resolve remains undimmed.

For the full report on Huntington’s disease from which this post was excerpted, including an in-depth look at the disease’s etiology, subtypes, incidence and prevalence, treatments and more, click here.