Characterization of the phenotype with cognitive impairment and protein mislocalization in SCA34.

OBJECTIVE: To better characterize the neurologic and cognitive profile of patients with spinocerebellar ataxia 34 (SCA34) caused by ELOVL4 mutations and to demonstrate the presence of ELOVL4 cellular localization and distribution abnormalities in skin-derived fibroblasts. METHODS: We investigated a 5-generation French-Canadian kindred presenting with a late-onset cerebellar ataxia and recruited age- and education-matched controls to evaluate the presence of neurocognitive impairment. Immunohistochemistry of dermal fibroblasts derived from a patient's skin biopsy was performed. RESULTS: Patients had a late-onset slowly progressive cerebellar syndrome (mean age at onset 47 years; range 32-60 years) characterized by truncal and limb ataxia, dysarthria, hypometric saccades, and saccadic pursuits. No patient had past or current signs of erythrokeratodermia variabilis, which had previously been reported. MRI revealed cerebellar atrophy, with pontine atrophy (4 of 6 patients), and cruciform hypersignal in the pons (2 of 6 patients). Fluorodeoxyglucose-PET showed diffuse cerebellar hypometabolism in all 5 tested patients with subtle parietal hypometabolism in 3. Significant cognitive deficits were found in executive functioning, along with apparent visuospatial, attention, and psychiatric involvement. Immunohistochemistry of dermal fibroblasts showed mislocalization of the ELOVL4 protein, which appeared punctate and aggregated, supporting a dominant negative effect of the mutation on protein localization. CONCLUSIONS: Our findings support the pathogenicity of ELOVL4 mutations in cerebellar dysfunction and provide a detailed characterization of the SCA34 phenotype, with neurocognitive changes typical of the cerebellar cognitive-affective syndrome.

Paresthesia and sensory disturbances associated with 2009 pandemic vaccine receipt: Clinical features and risk factors.

BACKGROUND: Paresthesia was the third-most-common adverse event following immunization (AEFI) with 2009 monovalent AS03-adjuvanted A(H1N1)pdm09 vaccine in Quebec, Canada and was also frequently reported in Europe. This study assessed clinical features and risk factors associated with this unexpected AEFI. METHODS: Reports to the passive surveillance system were summarized. A case-control study was conducted to assess risk factors and additional investigations were undertaken among cases with symptoms persisting ≥12 months. RESULTS: There were 328 reports of paresthesia affecting the vaccinated arm (58%), but also face (45%), lower limbs (40%) and back/thorax (23%) with numbness but also muscle weakness (61%), motor impairment (61%), generalized myalgia (37%), visual (14%) and/or speech effects (15%). Reporting rate was highest in women of reproductive age, peaking at 30-39 years-old (28/100,000 doses administered) and exceeding that of men of the same age (7/100,000 doses) by 4-fold. Median time to onset was 2h. Symptoms subsided within one week in 37% but lasted ≥6 months in 26%. No consistent or objective neurological findings were identified. Risk was increased with allergy history, respiratory illness the day of vaccination, depressive symptoms and family history of pulmonary disease, but decreased with physical activity the day of vaccination, and regular weekly alcohol consumption. CONCLUSION: Paresthesia following 2009 pandemic vaccine receipt lasted several weeks and included other motor-sensory disturbances in an important subset of patients. Although it does not correspond with known neurological disease, and causality remains uncertain, further investigation is warranted to understand the nature and frequency of paresthesia as a possible AEFI with influenza vaccines.