Huntington's Disease and Huntington's Disease-like 2 (HDL2) in Martinique

Area of Science:

• Neurology
• Genetics
• Rare Diseases

Background:

• Huntington's Disease-like 2 (HDL2) shares clinical similarities with Huntington's Disease (HD) and is primarily observed in individuals with African ancestry.
• The prevalence and clinical characteristics of HDL2 and HD in the Caribbean, specifically Martinique, were previously underexplored.

Purpose of the Study:

• To comprehensively characterize patients with Huntington's Disease (HD) and Huntington's Disease-like 2 (HDL2) in Martinique.
• To compare the clinical features, genetic factors, and disease progression of HD and HDL2 in this population.

Main Methods:

• Retrospective analysis of all HD and HDL2 patients over 20 years at a single neurology center in Martinique.
• Collection of longitudinal clinical data, Unified Huntington's Disease Rating Scale (UHDRS) scores, and CAG repeat lengths.

Main Results:

• The combined minimum prevalence of HD and HDL2 in Martinique was 7.77/100,000.
• HDL2 patients were predominantly male (83%) with motor symptoms as the most frequent initial manifestation, similar to HD.
• Both diseases exhibited negative correlation between repeat length and age of onset, progressive worsening of motor and functional scores in HDL2 mirroring HD, and significant inter- and intra-familial heterogeneity.

Conclusions:

• HDL2 is nearly as prevalent as HD in Martinique, indicating its significant presence in the region.
• The study confirms strong genotype-phenotype correlations and similar disease courses between HD and HDL2, while emphasizing HDL2's heterogeneity and germline instability.
• The findings are limited by the small number of HDL2 families, necessitating cautious interpretation.