Late-onset Huntington’s disease (emerging at age 59 or older), progresses similarly to common-onset Huntington’s except that late-onset patients more frequently showed gait and balance problems as their first symptom, new research has found.
This finding suggests that observing problems with gait and balance might be helpful in diagnosing late-onset Huntington’s disease in elderly patients.
The study, “Clinical and genetic characteristics of late-onset Huntington’s disease,” was published in the journal Parkinsonism and Related Disorders.
Huntington’s disease is a neurodegenerative disease and the age of onset usually is in the range of 30-50. However, for a substantial number of Huntington’s patients, symptoms and signs start at 59 or older.
It is generally accepted that late-onset Huntington’s is not as widespread and is less severe than common-onset Huntington’s disease, but studies show that anywhere from one in 20 to one in four patients with Huntington’s disease present with late-onset.
There are a few reasons why these studies vary so greatly in the frequency of late-onset Huntington’s disease. For one, the group sizes of patients examined were relatively small, so they may not be representative of the frequency of late-onset Huntington’s disease. Also, because late-onset symptoms begin later than the generally accepted age range for Huntington’s disease, many patients with late-onset Huntington’s disease may not have been diagnosed properly and, therefore, excluded from Huntington’s disease databases.
For these reasons, researchers at the Maastricht University Medical Center in the Netherlands decided to provide an updated understanding of the rate and symptoms of late-onset Huntington’s disease compared to common-onset Huntington’s disease patients.
To do so, they examined the largest group of Huntington’s patients to date using the European Huntington’s Disease Registry Database (REGISTRY), a huge study recording the natural course, clinical spectrum, and management of Huntington’s disease in 140 centers in 17 European and three non-European countries.
“This study represents the largest cohort study in literature describing the pheno- and genotype of late-onset Huntington’s disease patients and is therefore statistically more reliable,” researchers wrote.
Of nearly 10,000 patients in the database, the researchers examined only patients who were all confirmed for Huntington’s with CAG repeat expansions (the genetic hallmark for the disease), those who had a an estimated age of onset, and were examined for Huntington’s disease symptoms. This left the team with about 4,000 patients to study.
The proportion of late-onset Huntington’s disease patients in the REGISTRY database was about one in nine patients. “Possible explanations for the increase in prevalence include more accurate diagnostics, genetic testing, and better and more readily available symptomatic therapies, certainly in combination with an overall longer life expectancy,” researchers wrote.
Consistent with previous findings, the CAG repeat length and prevalence of disease in family history for late-onset Huntington’s disease was far lower compared to common-onset. This later finding “might make diagnosing Huntington’s disease more difficult in this population,” researchers noted.
In contrast to previous studies, disease progression was not milder in late-onset Huntington’s, however, motor progression tended to be slower. Also, the researchers found noteworthy differences in the presentation of Huntington’s disease symptoms between common- and late-onset patients.
They found that late-onset patients presented more frequently with motor symptoms and gait and balance problems as the first symptom, whereas the number of patients with behavioral symptoms was significantly higher in the common-onset group.
“[T]he balance and gait problems as first symptom might be helpful in diagnosing Huntington’s disease in elderly patients with a clear chorea [involuntary, unpredictable body movements], mild or no behavioral problems and a negative family history,” researchers concluded.