EuroEPINOMICS (European Science Foundation through national funding organisations), Epicure and EpiPGX (Sixth Framework Programme and Seventh Framework Programme of the European Commission), Research Unit FOR2715 (German Research Foundation and Luxembourg National Research Fund).

IMPORTANCE The autosomal dominant spinocerebellar ataxias (SCAs) are a complex group of neurodegenerative disorders with significant genetic heterogeneity. Despite the identification of 20 SCA genes, the cause of the disorder in a significant proportion of families with SCA remains unexplained. In 1972, a French-Canadian family segregating a combination of SCA and erythrokeratodermia variabilis (EKV) in an autosomal dominant fashion was described.OBJECTIVE To map and identify the causative gene in this large family with SCA and EKV using a combination of linkage analysis and whole-exome sequencing. DESIGN, SETTING, AND PARTICIPANTSA total of 32 individuals from the family have undergone complete neurologic and dermatologic examinations.MAIN OUTCOMES AND MEASURES Mutations in ELOVL4 have been reported in families with macular degeneration. Recently, homozygous mutations were found in patients with ichthyosis, spastic paraplegia, and severe neurodevelopmental defects. In the present study, we report on a heterozygote mutation in ELOVL4 in affected individuals from the family with SCA and EKV. The mutation segregates with a milder phenotype consisting of early-onset patches of erythema and hyperkeratosis, as well as SCA manifesting in the fourth or fifth decade of life. RESULTSWe describe the mapping and the identification of a c.504G>C transversion in ELOVL4 resulting in the p.L168F substitution. We also provide clinical characterization of the phenotypes in 19 mutation carriers. CONCLUSIONS AND RELEVANCEWe report, to our knowledge, the first mutation in ELOVL4 that is associated with SCA and EKV. This gene encodes a member of the elongase family, which is responsible for the elongation of very long-chain fatty acids (at least 26 carbons). These fatty acids participate in a wide variety of physiological functions, including skin barrier formation and peroxisome β-oxidation. Overall, these results provide additional insight into the pathogenesis of these complex neurodegenerative disorders.

SUMMARYObjective: We recently reported a Q555X mutation of synapsin 1 (SYN1) on chromosome Xp11-q21 in a family segregating partial epilepsy and autistic spectrum disorder. Herein, we provide a detailed description of the epileptic syndrome in the original family. Methods: A total of 34 members from a large French-Canadian family were evaluated. Family members with seizures or epilepsy underwent (when possible) clinical, neuropsychological, electrophysiologic, and neuroimaging assessments. Results: Epilepsy was diagnosed in 10 family members (4 deceased, 6 living). In addition to occasional spontaneous complex partial seizures, seven family members clearly had reflex seizures triggered by bathing or showering. Hippocampal atrophy was found in two of five epileptic family members family members who underwent magnetic resonance (MR) imaging. Video-electroencephalography (EEG) recordings of three triggered seizures in two affected members showed rhythmic theta activity over temporal head regions. Ictal single-photon emission computed tomography (SPECT) showed temporoinsular perfusion changes. Detailed neuropsychological assessments revealed that SYN1 Q555X male mutation carriers showed specific language impairment and mild autistic spectrum disorder. Female carriers also exhibited reading impairments and febrile seizures but no chronic epilepsy. Significance: Available evidence suggests that impaired SYN1 function is associated with hyperexcitability of the temporoinsular network and disturbance of high mental functions such as language and social interaction. The presence of reflex bathing seizures, a most peculiar clinical feature, could be helpful in identifying other patients with this syndrome.