Huntington Disease (HD)

Huntington disease (HD) is a rare neurodegenerative disease caused by an abnormal expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the huntingtin (HTT) gene. This mutation results in the expression of a mutant form of huntingtin protein. The toxic protein accumulates in neurons, impairing their function and survival and subsequently causing motor abnormalities, cognitive impairments, psychiatric symptoms, progressive disability, loss of independence, and ultimately death.¹

In several studies discussed below, comorbidities in patients with HD were found to include depression, dementia, dysphagia, obsessive-compulsive disorder, insomnia, neurosis, bipolar affective disorders, rheumatoid diseases, arterial hypertension, sleep disorders, gastric ulcers, allergies, and retinopathy.^2-4 

Studies on Comorbidities of HD 

2019 German Study

In a recent study of comorbidities associated with HD, depression was found to be the most common, affecting approximately 42.9% of patients, with females more frequently affected than males. Other comorbidities of HD were dementia (diagnosed in 37.7% of patients), urinary incontinence (32.5% of patients), extrapyramidal and movement disorders (30.5% of patients), dysphagia (28.6% of patients), and disorders of lipoprotein metabolism (28.2% of patients, with females more frequently affected than males).²

Read more about HD diagnosis

2020 Polish Study

Another study, based on surveys collected at 2 European Huntington’s Disease Network (EHDN) sites in Poland, compared the prevalence of comorbidities in patients with HD with that of healthy controls and subdivided the recorded comorbidities into musculoskeletal, cardiovascular, gastrointestinal, neurological, thyroid, psychiatric, and ophthalmologic categories.³

The study found that the prevalence of comorbidities, particularly those in the musculoskeletal, cardiovascular, and psychiatric categories, was generally higher in patients with HD than in the control group. The prevalence of psychiatric conditions was found to be highest in patients with symptomatic HD. The prevalence of musculoskeletal and cardiovascular conditions was also found to be significantly higher in patients with HD than in the control population.³

In comparison with controls, patients with symptomatic HD were found to have a significantly higher incidence of neurological and gastrointestinal conditions. Comorbidity rates in the allergy and ophthalmologic categories were also higher in patients with HD than in the control population.³

Read more about HD clinical features

Psychiatric Comorbidities

The recorded psychiatric comorbidities include obsessive-compulsive disorder, depression, recurrent depressive disorder, organic mood disorders, insomnia, bipolar affective disorders, dementia, and neurosis.³

Musculoskeletal Comorbidities

Common musculoskeletal comorbidities in this study include injuries (due to involuntary movements), articular degeneration disorders, and rheumatoid diseases. Other musculoskeletal comorbidities recorded during the survey included gonarthrosis, scoliosis, cervical and/or lumbosacral spondylosis, intervertebral disc degeneration, discopathy, back pain, and osteoporosis. Noted injuries included joint dislocation; strain or luxation; fractures of various bones; injury of ligaments, tendons, or muscles; and head injury.³

Cardiovascular Comorbidities

Comorbidities in the cardiovascular category include arterial hypertension (most frequent), cardiac arrhythmias, tachycardia, valve insufficiency, vein insufficiency, atherosclerosis, acute myocardial infarction, chronic ischemic heart disease, cerebral infarction, and varicose veins in the lower extremities.³

Neurological Comorbidities

Recorded neurological comorbidities include sleep disorders, meningitis, epilepsy, insomnia, carpal tunnel syndrome, nerve root and plexus disorders.³

Gastrointestinal Comorbidities

Common gastrointestinal comorbidities include duodenal ulcer, gastric ulcer, gastroesophageal reflux disease, acute appendicitis, gastritis, irritable bowel syndrome, inflammatory bowel disease, rectal polyps, colon polyps, cholelithiasis, and cholecystitis. The comorbidities in the gastrointestinal category may be related to abnormal bite, effects of medications, or metabolic challenges.³

Allergic Comorbidities

Several allergic conditions can occur in patients with HD, including drug allergy, asthma, allergic rhinitis, and atopic dermatitis.³

Ophthalmologic Comorbidities

Ophthalmologic comorbidities were found to include glaucoma, retinopathy, myopia, and cataracts.³

Read more about HD treatment

2023 Swedish Study

A recent study used nationwide data from linked Swedish registries between 2002 and 2019 to describe the occurrence of comorbidities, both acute and chronic, in a cohort of 1492 patients with HD.⁴ 

The study found a higher incidence rate of many comorbidities, including obsessive-compulsive disorder, acute psychotic episodes, communication problems, depression, anxiety, dementia, pneumonia, constipation, and fractures, in individuals with adult-onset HD than in controls. In those with juvenile-onset HD, the incidence rates of epilepsy, constipation, and acute respiratory symptoms were higher.⁴

Read more about HD prognosis

References

1. Ajitkumar A, De Jesus O. Huntington disease. StatPearls [Internet]. Updated February 12, 2023. Accessed August 14, 2023.
2. Ohlmeier C, Saum KU, Galetzka W, Beier D, Gothe H. Epidemiology and health care utilization of patients suffering from Huntington’s disease in Germany: real world evidence based on German claims data. BMC Neurol. 2019;19(1):318. doi:10.1186/s12883-019-1556-3
3. Zielonka D, Witkowski G, Puch EA, et al. Prevalence of non-psychiatric comorbidities in pre-symptomatic and symptomatic Huntington’s disease gene carriers in Poland. Front Med (Lausanne). 2020;7:79. doi:10.3389/fmed.2020.00079
4. Furby H, Moore S, Nordstroem AL, et al. Comorbidities and clinical outcomes in adult- and juvenile-onset Huntington’s disease: a study of linked Swedish National Registries (2002–2019). J Neurol. 2023;270(2):864-876. doi:10.1007/s00415-022-11418-y

Reviewed by Harshi Dhingra, MD, on 8/15/2023.

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Erum Naqvi, PhD

Erum Naqvi obtained her Ph.D. in Molecular Medicine from Hannover Medical School (Germany) after completing her Masters in Biomedical Science and Bachelors in Microbiology from University of Delhi (India). She has several years of experience as a science writer.