F09 Late onset huntington’s disease phenotype progression. 2 years follow-up in 220 patients from enroll-HD PDS4

Huntington’s disease (HD) onset typically occurs in mid adulthood however, late onset phenotype with onset 60 years and over (LoHD) is recently gaining attention. We examined the baseline characteristics of 220 LoHD patients and their clinical, cognitive and behavioral correlates at two consecutive timepoints over 2 years. This is a retrospective observational study on 220 European LoHD patients from the Enroll-HD dataset with 2 consecutive annual follow-up visits. Linear models using repeated measures Anova were performed to investigate changes over time. LoHD patients were 114 Males (51.8%) and 106 Females (48.2%), their mean age at baseline visit (t0) was 70.0 ±5.0 years, with disease duration 6.34±3.89 years. Mean CAGn was respectively 40.75±1.29 in larger allele, and 18.19±2.86 in normal allele. In 18% of LoHD patients HD family history was not traceable. Body Mass index BMI, UHDRS Total functional Capacity TFC & Total Motor Score TMS, PBAs composite scores, MMSE and a cognitive battery restricted to the assessment of executive functions were reported at t0 and compared at t1 (375 ±61.01 days) and t2 (746.39±74.8 days). BMI remained stable at t1 and t2 , TMS significantly worsened at t2 and TFC was reduced of 0.80 point at t1 and 1.41 at t2. No significant cognitive changes over two years on MMSE, Phonological fluency and Symbol Digit Span Modalities Test, Trail Making Test and Stroop Interference Test. Lower scores detected at t2 for Categorial Fluency (animals), Stroop color reading and word reading. No significant changes were detected over two years in PBA-s composite scores rating depression/anxiety/suicidality, irritability and aggressivity, psychosis, apathy. LoHD phenotype clinical progression is characterized by significant reduction in daily functionality and worsening in motor symptoms over 2 years. In cognitive performance significant changes were detected only in few specific tasks, requiring further investigation.