Huntington's disease like-2 neuropathology.

Huntington's disease like-2 (HDL-2) neurodegeneration is a recently described autosomal dominant disorder with features similar to Huntington's disease (HD). Only one case report has described neuropathology from an affected patient. We describe the clinical presentation and illustrate the pathology in two additional molecularly confirmed patients, compare these with the previously published case, and contrast them with HD. We examined two patients with HDL-2. Their charts were reviewed, their brains were examined using standard neuropathology techniques, including immunoperoxidase stains, and their diagnoses were confirmed with a PCR-based assay for repeat length. The first patient presented with obsessive suspiciousness, while the second had depression and decreased visual acuity. Both patients developed increased tone and cogwheel rigidity, but neither developed choreoathetosis. Extensive degeneration affected the caudate nucleus and putamen, especially dorsally and laterally. In addition, the first patient showed lateral temporal, lateral frontal, and orbitofrontal cortical atrophy, while the second patient displayed marked degeneration in the occipital and parietal cortices. Neither patient showed significant changes in the cerebellum or brainstem. Both cases had ubiquitin-immunoreactive neuronal intranuclear inclusions (NII). The patients with of HDL-2 reviewed here were remarkable for significant frontal inhibition with parkinsonism, a lack of choreiform movements, and African ancestry. Pathologically, HDL-2 is similar to HD in its effect on the neostriatum but may differ, at least in some cases, in its degree of focal cortical involvement, including the occipital lobe.     

Case of maternally transmitted juvenile Huntington's disease with a very large trinucleotide repeat.

We describe and present a video of a patient with maternally inherited juvenile Huntington's disease (HD) caused by a very large (108-repeat) expansion. Maternally transmitted very large trinucleotide repeats (>100) are extremely rare in juvenile HD and may represent instability during female gametogenesis.     

Short-term effects of tetrabenazine on chorea associated with Huntington's disease.

We sought to assess the short-term clinical effects of tetrabenazine (TBZ) on choreic movements in Huntington's disease patients. A total of 10 patients on stable doses of TBZ were enrolled in this observational study. Patients took their evening dose of TBZ and presented the next day to the Baylor College of Medicine Movement Disorders Clinic without taking the usual morning dose. They were assessed using the Unified Huntington's Disease Rating Scale (UHDRS) motor assessment and Beck Depression Inventory. The usual morning dose of TBZ was then administered and patients were followed with serial UHDRS motor examinations approximately every 2 hours until choreic movements subsided and then returned. TBZ decreased the UHDRS chorea score on average 42.4% +/- 17.8%. The duration of effect varied from a minimum of 3.2 hours to a maximum of 8.1 hours (mean = 5.4 +/- 1.3). No patient experienced an adverse event related to TBZ or its withdrawal. During short-term follow-up after a single dose, TBZ improves chorea for approximately 5 hours.     

Open-label pilot study of levetiracetam (Keppra) for the treatment of chorea in Huntington's disease.

The objective of this study is to evaluate the tolerability and preliminary efficacy of levetiracetam (LEV) in reducing chorea in Huntington's disease (HD) patients in a prospective open-label pilot study. Nine HD patients with chorea were treated with LEV in doses up to 3,000 mg/day for up to 48 days. The primary endpoint measure was the Unified Huntington's Disease Rating Scale (UHDRS) chorea subscore. The mean dose (+/-SD) of LEV at endpoint was 2,583.3 +/- 1,020.6 mg/day. Mean UHDRS chorea score decreased from 12.6 +/- 3.0 at baseline to 6.7 +/- 4.3 at endpoint (P = 0.01). There was no significant change in UHDRS total motor scores (38.8 +/- 11.4 at baseline and 33.6 +/- 26.7 at endpoint; P = 0.24). Somnolence contributed to a 33% drop-out rate, and 3 patients developed Parkinsonism. Results of this open label study suggest that LEV may be efficacious in reducing chorea in HD patients.     

Huntington's disease as caused by 34 CAG repeats

Huntington's disease (HD) is an autosomal dominantly inherited neurodegenerative disorder caused by an abnormal expansion of a polymorphic stretch of CAG repeats in the coding 5′ part of the HD gene on chromosome 4p. Expansions of CAG blocks beyond 35 repeats are associated with the clinical presentation of HD. There is an intermediate range of rare alleles between 27 and 35 CAG repeats with a higher risk for further expansion in subsequent generations. Here, we report a 75‐year‐old male with clinical features of HD and 34 CAG repeat units. © 2008 Movement Disorder Society     

Late-onset Huntington's disease: Diagnostic and prognostic considerations

ObjectiveTo address diagnostic and prognostic issues in patients with late-onset Huntington's disease (HD).MethodsWe analyzed a cohort of 41 late-onset (≥60 years) HD patients and compared them to 39 late-onset patients referred for HD testing that were negative for the HD-expansion and to 290 usual-onset (20–59 years) HD patients. Disease severity was assessed by the Total Functional Capacity Scale.ResultsLate-onset HD comprised 11.5% of our HD cohort. In total, 70.7% of late-onset HD patients had positive family history compared to 15.4% of late-onset expansion-negative patients (p < 0.001). Clinical features at onset or presentation could not usefully distinguish between late-onset expansion-positive and negative patients, excepting hemichorea, which was absent from the HD group (p = 0.024). Chorea was the first clinical feature in 53.7% and a presenting feature in 90.2% of late-onset HD. The mutation hit rate for late-onset patients was 51.3%, lower than in usual-onset patients (p = 0.04). Frequencies of chorea, cognitive impairment and psychiatric manifestations at onset or presentation were not significantly different between late-onset and usual-onset HD patients. Gait unsteadiness however was more common at presentation in late-onset HD (p = 0.007). Late-onset HD patients reached a severe stage of illness on average 2.8 years earlier than usual-onset HD patients (p = 0.046).ConclusionsA positive family history suggestive of HD, although absent in a third of patients, remains a helpful clue in diagnosing late-onset HD. Prognosis of late-onset HD in terms of Total Functional Capacity appears no better and shows a trend of being somewhat less favorable compared to usual-onset HD.     

The relationship between CAG repeat length and clinical progression in Huntington's disease

The objective of this study was to examine the relationship between CAG repeat length (CAGn) and clinical progression in patients with Huntington's disease (HD). There are conflicting reports about the relationship between CAGn and clinical progression of HD. We conducted an analysis of data from the Coenzyme Q10 and Remacemide Evaluation in Huntington's Disease (CARE‐HD) clinical trial. We modeled progression over 30 months on the Unified Huntington's Disease Rating Scale (UHDRS) and supplemental neuropsychological and behavioral tests using multiple linear regression. Mean subject age was 47.9 ± 10.5 years and mean CAGn was 45.0 ± 4.1. Multiple linear regression revealed statistically significant associations between CAGn and worsening on several motor, cognitive, and functional outcomes, but not behavioral outcomes. Many effects were clinically important; 10 additional CAG repeats were associated with an 81% increase in progression on the Independence Scale. These associations were not observed in the absence of age adjustment. Age at the time of assessment confounds the association between CAGn and progression. Adjusting for age shows that longer CAGn is associated with greater clinical progression of HD. This finding may account for the variable results from previous studies examining CAGn and progression. Adjusting for CAGn may be important for clinical trials. © 2008 Movement Disorder Society     

Tongue force analysis assesses motor phenotype in premanifest and symptomatic Huntington's disease

Motor symptoms in Huntington's Disease (HD) are commonly assessed by the Unified Huntington's Disease Rating Scale‐Total Motor Score (UHDRS‐TMS). However, the UHDRS‐TMS is limited by interrater variability, its categorical nature, and insensitivity in premanifest subjects. More objective and quantitative measures of motor phenotype may complement the use of the UHDRS‐TMS as outcome measure and increase the power and sensitivity of clinical trials. Deficits in tongue protrusion are well acknowledged in HD and constitute a subitem of the UHDRS‐TMS. We, therefore, investigated whether objective and quantitative assessment of tongue protrusion forces (TPF) provides measures that (1) correlate to the severity of motor phenotype detected in the UHDRS‐TMS in symptomatic HD, (2) detect a motor phenotype in premanifest HD gene‐carriers, and (3) exhibit a correlation to the genotype as assessed by a disease burden score (based on CAG‐repeat length and age). Using a precalibrated force transducer, the ability of premanifest gene carriers (n = 15) and subjects with symptomatic HD (n = 20) to generate and maintain isometric TPF at three target force levels (0.25, 0.5, and 1.0 N) was assessed and compared with age‐matched controls (n = 20) in a cross‐sectional study. Measures of variability of TPF and tongue contact time distinguished controls, premanifest, and symptomatic HD groups and correlated to the UHDRS‐TMS and disease burden score, suggesting a strong genotype‐phenotype correlation. Group distinction was most reliable at the lowest target force level. We conclude that assessment of TPF may be a useful objective and quantitative marker of motor dysfunction in premanifest and symptomatic HD. © 2010 Movement Disorder Society     

A pilot study using nabilone for symptomatic treatment in Huntington's disease

Pilot study of nabilone in Huntington's disease (HD). Double‐blind, placebo‐controlled, cross‐over study of nabilone versus placebo. Primary outcome, Unified Huntington's Disease Rating Scale (UHDRS) total motor score. Secondary measures: UHDRS subsections for chorea, cognition and behavior, and neuropsychiatric inventory (NPI). 44 randomized patients received either nabilone (1 or 2 mg) followed by placebo (n = 22), or placebo followed by nabilone (n = 22). Recruiting was straightforward. Nabilone safe and well tolerated, no psychotic episodes. Assessment of either dose of nabilone versus placebo showed a treatment difference of 0.86 (95% CI: ?1.8 to 3.52) for total motor score; 1.68 (95% CI: 0.44 to 2.92) for chorea; 3.57 (95% CI: ?3.41 to 10.55) for UHDRS cognition; 4.01 (95% CI: ?0.11 to 8.13) for UHDRS behavior, and 6.43 (95% CI: 0.2 to 12.66) for the NPI. Larger longer RCT of nabilone in HD is feasible and warranted. © 2009 Movement Disorder Society     

Phenotypic features of Huntington's disease-like 2.

Huntington's disease-like 2 is an autosomal dominantly inherited disorder due to an expansion of trinucleotide repeats. It resembles classic Huntington's disease in clinical phenotype, inheritance pattern, and neuropathological features. We highlight the clinical features of this disorder, including chorea, dystonia, parkinsonism, and cognitive deficits.     

Hyperhomocysteinaemia in treated patients with Huntington's disease homocysteine in HD.

Significantly increased plasma total homocysteine levels (t-Hcys) appeared in treated Huntington disease (HD) patients compared to controls and untreated HD subjects. Because the protein Huntingtin interacts with the homocysteine metabolism modulating enzyme cystathionine beta-synthase, we hypothesize that homocysteine promotes neurodegeneration in HD.     

Reduced Purkinje cell density in Huntington's disease

We studied, in a "blind" and quantitative fashion, the density of cerebellar Purkinje cells in 17 adult cases of Huntington's disease (HD), 17 patients with other movement disorders, 17 with schizophrenia, and 23 normal controls. There was a highly significant reduction in Purkinje cell density in HD compared with any of the other three groups. A much smaller difference in neuronal density between patients with other movement disorders and normal controls was barely significant. Eight of the 17 HD patients and only 1 of the other 57 subjects had Purkinje cell density less than 50% of the mean for the normal controls. The low density of Purkinje cells in HD could not be attributed to aging, seizures, or cause of death, nor was it merely a part of a generalized brain atrophy. The loss of large Purkinje cells suggests that the neuronal loss in HD may not be restricted to small and medium-size neurons.     

The Wilson films--Huntington's chorea

Wilson's Queen Square Case 9 with Huntington's chorea shows a 68-year-old man with mild to moderate generalized chorea, impaired fixation, and probable cognitive decline in keeping with a diagnosis of Huntington's disease (HD). An age of onset in the late sixties and a negative family history suggest a relatively small expanded trinucleotide repeat in the HTT gene in the patient and reduced penetrance of an even shorter repeat allele in one of his parents. A highly sensitive and specific gene test has been offered worldwide for diagnostic testing of HD for almost two decades. This test, obviously unavailable at Wilson's times, became the historic frontrunner for guidelines of symptomatic, presymptomatic, and prenatal testing for an adult-onset neurodegenerative disorder. Regarding treatment of HD, however, we are still awaiting the successful translation of research results into the development of effective cause-directed, neuropreventive and neurorestaurative therapies.     

Seizures in juvenile Huntington's disease: Frequency and characterization in a multicenter cohort

Little is known about the epilepsy that often occurs in the juvenile form of Huntington's disease (HD), but is absent from the adult‐onset form. The primary aim of this study was to characterize the seizures in juvenile HD (JHD) subjects with regard to frequency, semiology, defining EEG characteristics, and response to antiepileptic agents. A multicenter, retrospective cohort was identified by database query and/or chart review. Data on age of HD onset, primary HD manifestations, number of CAG repeats, the presence or absence of seizures, seizure type(s), antiepileptic drugs used, subjects' response to antiepileptic drugs (AEDs), and EEG results were assembled, where available. Ninety subjects with genetically confirmed JHD were included. Seizures were present in 38% of subjects and were more likely to occur with younger ages of HD onset. Generalized tonic‐clonic seizures were the most common seizure type, followed by tonic, myoclonic, and staring spells. Multiple seizure types commonly occurred within the same individual. Data on EEG findings and AED usage are presented. Seizure risk in JHD increases with younger age of HD onset. Our ability to draw firm conclusions about defining EEG characteristics and response to AEDs was limited by the retrospective nature of the study. Future prospective studies are required. © 2012 Movement Disorder Society