Late Onset Huntington Disease: Phenotypic and Genotypic Characteristics of 10 Cases in Argentina.

Background: Huntington's disease (HD) is a neurodegenerative disorder that includes motor, psychiatric and cognitive manifestations with typical onset of symptoms is in the forties. A percentage of patients (4.4%-11.5%) may be exceptions to this and manifest symptoms later (>60 years old). Diagnosis of Late onset HD (LoHD) can be a challenge, due to the low suspicion of the disease at this age. Objective: To review the genotype and phenotype of LoHD in an Argentinian cohort. Methods: We reviewed the medical records and genetic testing of a total of 95 individuals with clinical and molecular diagnosis of Huntington's disease, based on 2 institution's registry. Results: Among our HD cohort, 10 patients (10.52%) had LoHD, with variable results regarding family history. The average of repetitions of the expanded allele was 40 (range 38-44). All cases had mild motor symptoms at onset. Conclusions: Late onset HD can be a diagnostic challenge, due to its slow progression, unawareness of manifestations among patients and in many cases, mild symptomatology that does not warrant medical attention.