What do we know about Late Onset Huntington's Disease?

Area of Science:

• Neurology
• Genetics
• Epidemiology

Background:

• Huntington's disease (HD) typically manifests in the fourth decade.
• Late onset Huntington's disease (LoHD), defined as onset over 60 years, accounts for 4.4-11.5% of HD cases.
• Diagnosis of LoHD can be challenging due to its lower perceived prevalence in older adults.

Purpose of the Study:

• To review the epidemiology, genotype, and phenotype of Late onset Huntington's disease (LoHD).

Main Methods:

• Systematic literature search of MEDLINE, EMBASE, and Web of Science databases (inception-November 2016).
• Inclusion of studies reporting clinical phenotype of LoHD for more than one participant.
• Consultation with content experts for additional studies.

Main Results:

• 20 studies were identified, revealing LoHD constitutes a significant proportion of HD cases, potentially increasing.
• CAG repeat lengths in LoHD are typically ≤44, with variable family history presentation (3-68%).
• While motor symptoms are common, 29.2% of cases present with non-motor features; cognitive impairment may be a primary source of disability, and progression may be slower.

Conclusions:

• Late onset Huntington's disease (LoHD) represents a substantial portion of new HD diagnoses and exhibits unique characteristics.
• Further research into LoHD populations is crucial for improving clinical diagnosis and management.