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Resumen Introduccion La ARCA1/SCAR8 es una heredoataxia recesiva causada por mutaciones en el gen SYNE1, que fue descrita inicialmente en familias francocanadienses (Quebec) con un sindrome cerebeloso puro. En la actualidad se reporta cada vez mas este tipo de ataxia en otras partes del mundo y con un fenotipo muy variable. Recientemente se han notificado casos de distrofia muscular, artrogriposis y miocardiopatia por mutaciones de este gen. Objetivos Describir los hallazgos clinicos y moleculares en 3 familias espanolas de diferente origen geografico, las primeras en las que se confirmo el diagnostico de ARCA1/SCAR8 con analisis molecular. Material y metodos Evaluacion clinica, pruebas paraclinicas y estudio genetico en 4 pacientes (3 varones y una mujer), diagnosticados en distintos servicios de neurologia espanoles. Resultados Los sintomas cerebelosos comenzaron en todos los casos en la tercera-cuarta decadas. Tras 15 anos de evolucion, 3 pacientes presentaban un sindrome cerebeloso puro similar a la descripcion original, mientras que un paciente con mas de 30 anos de evolucion presentaba tambien paralisis de mirada vertical, afectacion piramidal y moderado deterioro cognitivo. El estudio de resonancia magnetica mostro en todos los casos atrofia restringida al cerebelo. La secuenciacion de SYNE1 permitio identificar distintas variantes patogenicas en cada familia. Conclusiones La ARCA1/SCAR8 tiene una distribucion mundial con una gran diversidad de mutaciones en SYNE1. Ademas de ataxia puede dar lugar a un complejo fenotipo de inicio y gravedad muy variable.

Introduction In 2009, we described a possible founder effect of autosomal dominant Segawa disease in Cordoba (Spain) due to mutation c.265C>T (p. Q89*) in the GCH1 gene. We present a retrospective multicentre study aimed at improving our knowledge of Segawa disease in Spain and providing a detailed phenotypic-genotypic description of patients. Methods Clinical-genetic information were obtained from standardized questionnaires that were completed by the neurologists attending children and/or adults from 16 Spanish hospitals. Results Eighty subjects belonging to 24 pedigrees had heterozygous mutations in GCH1. Seven genetic variants have been described only in our cohort of patients, 5 of which are novel mutations. Five families not previously described with p. Q89* were detected in Andalusia due to a possible founder effect. The median latency to diagnosis was 5 years (IQR 0–16). The most frequent signs and/or symptoms were lower limb dystonia (38/56, 67.8%, p = 0.008) and diurnal fluctuations (38/56, 67.8%, p = 0.008). Diurnal fluctuations were not present in the phenotypes other than dystonia. Fifty-three of 56 symptomatic patients were treated with a levodopa/decarboxylase inhibitor for (mean ± SD) 12.4 ± 8.12 years, with 81% at doses lower than 350 mg/day (≤5 mg/kg/d in children). Eleven of 53 (20%) patients had non-responsive symptoms that affected daily life activities. Dyskinesias (4 subjects) were the most prominent adverse effects. Conclusion This study identifies 5 novel mutations and supports the hypothesis of a founder effect of p. Q89* in Andalusia. New insights are provided for the phenotypes and long-term treatment responses, which may improve early recognition and therapeutic management.

Objective: SPG4 is an autosomal dominant pure form of hereditary spastic paraplegia (HSP) caused by mutations in the SPAST gene. HSP is considered an upper motor neuron disorder characterized by progressive retrograde degeneration, or "dying-back" phenomenon, of the corticospinal tract's longest axons. Neuroimaging studies mainly focus on white matter changes and, although previous studies reported cortical thinning in complicated HSP forms, cortical changes remain unclear in SPG4 patients. This work aimed to compare changes in white matter microstructure and cortical thickness between 12 SPG4 patients and 22 healthy age-matched controls. We also explore whether white matter alterations are related to cortical thickness and their correlation with clinical symptoms. Methods: we used fixel-based analysis, an advanced diffusion-weighted imaging technique, and probabilistic tractography of the corticospinal tracts. We also analyzed cortical morphometry using whole-brain surface-based and atlas-based methods in sensorimotor areas. Results: SPG4 patients showed bilateral involvement in the corticospinal tracts; this was more intense in the distal portion than in the upper segments and was associated with the degree of clinical impairment. We found a significant correlation between disease severity and fiber density and cross-section of the corticospinal tracts. Furthermore, corticospinal tract changes were significantly correlated with bilateral cortical thinning in the precentral gyrus in SPG4 patients. Conclusions: Our data point to axonal damage of the corticospinal motor neurons in SPG4 patients might be related to cortical thinning in motor regions.

SPG4 is an autosomal dominant pure form of hereditary spastic paraplegia (HSP) caused by mutations in the SPAST gene. HSP is considered an upper motor neuron disorder characterized by progressive spasticity and weakness of the lower limbs caused by degeneration of the corticospinal tract. In other neurodegenerative motor disorders, the thalamus and basal ganglia are affected, with a considerable impact on disease progression. However, only a few works have studied these brain structures in HSP, mainly in complex forms of this disease. Our research aims to detect potential alterations in the volume and shape of the thalamus and various basal ganglia structures by comparing 12 patients with pure HSP and 18 healthy controls. We used two neuroimaging procedures: automated segmentation of the subcortical structures (thalamus, hippocampus, caudate nucleus, globus pallidus, and putamen) in native space and shape analysis of the structures. We found a significant reduction in thalamic volume bilaterally, as well as an inward deformation, mainly in the sensory-motor thalamic regions in patients with pure HSP and a mutation in SPG4. We also observed a significant negative correlation between the shape of the thalamus and clinical scores (the Spastic Paraplegia Rating Scale score and disease duration). Moreover, we found a ‘Group × Age’ interaction that was closely related to the severity of the disease. No differences in volume or in shape were found in the remaining subcortical structures studied. Our results suggest that changes in structure of the thalamus could be an imaging biomarker of disease progression in pHSP.

SCA36 is an autosomal dominant spinocerebellar ataxia (SCA) affecting many families from Costa da Morte, a northwestern region of Spain. It is caused by an intronic GGCCTG repeat expansion in NOP56. In order to characterize the cognitive and affective manifestations of this cerebellar disease, a group of 30 SCA36 mutation carriers (11 preataxic and 19 ataxic patients) were assessed with a comprehensive battery of standardized tests. Phonological verbal fluency – but not semantic fluency – was already mildly impaired in preataxic subjects. In ataxic patients, both phonological and semantic fluencies were significantly below normal. Depression, while more frequent and prominent in ataxic patients, was also often present in the preataxic stage. This is the first systematic study supporting the presence of a mild cerebellar cognitive and affective syndrome in SCA36. Routine evaluation of cognitive and emotional spheres in SCA36 patients as well as asymptomatic mutation carriers should allow early detection and timely therapeutic intervention.

Background The spinocerebellar ataxias (SCAs) form a clinically, genetically, and pathological heterogeneous group of autosomal-dominant degenerative diseases. In particular, SCA36 is characterized by a late-onset, slowly progressive cerebellar syndrome typically associated with sensorineural hearing loss. This study was aimed at analyzing the neurodegenerative process underlying SCA36 through fluorodeoxyglucose positron emission tomography (FDG-PET) and MRI scans. Methods Twenty SCA36 patients underwent a study consisting of FDG-PET and MRI scans. Clinical motor evaluation was performed through the Scale for the Assessment and Rating of Ataxia (SARA). FDG-PET was carried out using a voxel-by-voxel and region-of-interest analysis. MRI evaluation was based on visual inspection and volumetric analysis. Results SARA ranged from 0 to 24.5 (4 patients asymptomatic, 3 with unspecific symptoms, and 13 with cerebellar signs). FDG-PET revealed hypometabolism in the asymptomatic stage in the vermis and right cerebellar hemisphere. In the ataxic stage, hypometabolism spread to both cerebellar hemispheres and the brain stem. MRI was normal in asymptomatic and preataxic individuals and showed superior cerebellar vermis atrophy early in the ataxic stage, diffuse cerebellar atrophy some years into the disease course, and a pattern of olivopontocerebellar atrophy in the oldest patients. There was no significant cerebellar atrophy in patients younger than 50 years. Conclusions We present the first FDG-PET study of SCA36 and one of the largest neuroimaging study of SCAs. Our results revealed neuronal dysfunctions in the vermis and right cerebellar hemisphere as soon as a decade before the onset of motor symptoms. In the ataxic stage, dysfunctions spread to both hemispheres and the brain stem. © 2016 International Parkinson and Movement Disorder Society.

Introduction The pathophysiology of PD (Parkinson's disease) has been related to the ubiquitin proteasome system and oxidative stress. Parkin acts as ubiquitin ligase on several substrates. Because genetic variants often have different frequencies across populations, population specific analyses are necessary to complement and validate results from genome-wide association studies. Methods We carried out an association study with genes coding for parkin substrates and cellular stress components in the Galician population (Northern Spain). SNCA and MAPT SNPs were also analyzed. We studied 75 SNPs in a discovery sample of 268 PD patients and 265 controls from Galicia. A replication sample of 271 patients and 260 controls was recruited from Mexico City. Results We observed significant association between PD and SNPs in MAPT. Nominal p-values < 0.05 were obtained in the Galician cohort for SNPs in SYT11, coding for synaptotagmin XI. These results were replicated in the Mexican sample. Discussion The associated markers lie within a ~ 140 kb strong linkage disequilibrium segment that harbors several candidate genes, including SYT11. SNPs from the GBA-SYT11-RAB25 region have been previously associated with PD, however the functionally relevant variants remain unknown. Our data support a likely role of genetic factors within 1q22 in PD susceptibility.

Objective:To assess the prevalence and clinical features of individuals affected by spinocerebellar ataxia 36 (SCA36) at a large tertiary referral center in the United States.Methods:A total of 577 patients with undiagnosed sporadic or familial cerebellar ataxia comprehensively evaluated at a tertiary referral ataxia center were molecularly evaluated for SCA36. Repeat primed PCR and fragment analysis were used to screen for the presence of a repeat expansion in the NOP56 gene.Results:Fragment analysis of triplet repeat primed PCR products identified a GGCCTG hexanucleotide repeat expansion in intron 1 of NOP56 in 4 index cases. These 4 SCA36-positive families comprised 2 distinct ethnic groups: white (European) (2) and Asian (Japanese [1] and Vietnamese [1]). Individuals affected by SCA36 exhibited typical clinical features with gait ataxia and age at onset ranging between 35 and 50 years. Patients also suffered from ataxic or spastic limbs, altered reflexes, abnormal ocular movement, and cognitive impairment.Conclusions:In a US population, SCA36 was observed to be a rare disorder, accounting for 0.7% (4/577 index cases) of disease in a large undiagnosed ataxia cohort.

Spinocerebellar ataxia 36 has been recently described in Japanese families as a new type of spinocerebellar ataxia with motor neuron signs. It is caused by a GGCCTG repeat expansion in intron 1 of NOP56 . Family interview and document research allowed us to reconstruct two extensive, multigenerational kindreds stemming from the same village (Costa da Morte in Galicia, Spain), in the 17th century. We found the presence of the spinocerebellar ataxia 36 mutation co-segregating with disease in these families in whom we had previously identified an ∼0.8 Mb linkage region to chromosome 20 p. Subsequent screening revealed the NOP56 expansion in eight additional Galician ataxia kindreds. While normal alleles contain 5–14 hexanucleotide repeats, expanded alleles range from ∼650 to 2500 repeats, within a shared haplotype. Further expansion of repeat size was frequent, especially upon paternal transmission, while instances of allele contraction were observed in maternal transmissions. We found a total of 63 individuals carrying the mutation, 44 of whom were confirmed to be clinically affected; over 400 people are at risk. We describe here the detailed clinical picture, consisting of a late-onset, slowly progressive cerebellar syndrome with variable eye movement abnormalities and sensorineural hearing loss. There were signs of denervation in the tongue, as well as mild pyramidal signs, but otherwise no signs of classical amyotrophic lateral sclerosis. Magnetic resonance imaging findings were consistent with the clinical course, showing atrophy of the cerebellar vermis in initial stages, later evolving to a pattern of olivo-ponto-cerebellar atrophy. We estimated the origin of the founder mutation in Galicia to have occurred ∼1275 years ago. Out of 160 Galician families with spinocerebellar ataxia, 10 (6.3%) were found to have spinocerebellar ataxia 36, while 15 (9.4%) showed other of the routinely tested dominant spinocerebellar ataxia types. Spinocerebellar ataxia 36 is thus, so far, the most frequent dominant spinocerebellar ataxia in this region, which may have implications for American countries associated with traditional Spanish emigration. * Abbreviations : SCA : spinocerebellar ataxia SNP : single nucleotide polymorphism TP-PCR : triplet repeat primed polymerase chain reaction

Neurofibromatosis type 1 (NF1) is a multisystem disease with autosomal dominant inheritance and complete penetrance diagnosed by clinical findings. Cutaneous neurofibromas are present in almost all adult patients in the dermis, epidermis or along the peripheral nerves. Plexiform neurofibromas are subcutaneous or deep lesions involving nerve plexuses or roots. Neurofibromas can degenerate into malignant tumors, with important prognostic implications. NF1 shows a broad clinic variability even within a single family. Exceptions are cases reporting the in-frame microdeletion c.2970_2972delAAT, presenting with the typical pigmentary features of NF1, but no cutaneous or plexiform neurofibromas. We report a patient with a de novo c.2970_2972delAAT mutation who had few café-au-lait spots, only 2 of which measured >15 mm, axillary and submammary freckling, a flat angioma extending over the neck, arm and trunk, a high arched palate, micrognathia, macrocephaly, pes cavus and scoliosis. There was complete absence of observable cutaneous neurofibromas as well as external plexiform neurofibromas. She had had epileptic seizures since childhood; however, a diagnosis of NF1 had not been confirmed until she was 38, partly due to the paucity of characteristic cutaneous stigmata. We confirm the association of the c.2970_2972delAAT mutation in NF1 with a particular clinical phenotype, especially with lack of detectable neurofibromas. For an appropriate management of patients and family counseling, molecular study of the NF1 gene should be considered in patients not fulfilling NIH criteria when other features suggestive of NF1 are present. In the absence of neurofibromas, starting NF1 testing with the screening of exon 17 may be worthwhile.

Resumen: Introducción: La expansión de los estudios genéticos está transformando la práctica de la Neurología y enfrenta a los servicios clínicos con nuevos retos, como la articulación del asesoramiento genético. La amplitud de los conocimientos tanto clínicos como moleculares precisos, así como la necesidad de una evaluación psicológica y apoyo familiar, especialmente en los análisis predictivos y planificación reproductiva, hacen necesario un enfoque multidisciplinar. Desarrollo: Las características principales de las enfermedades neurodegenerativas de base genética son el elevado nivel de especialización requerido —por tratarse de enfermedades poco comunes y de difícil diagnóstico— junto con su carácter generalmente progresivo, la ausencia de tratamientos eficaces, la problemática generada por la posibilidad de estudios predictivos y la interpretación de los resultados genéticos. El objetivo del asesoramiento genético es proporcionar la información suficiente y objetiva para que cada individuo pueda tomar sus propias decisiones sobre el estudio genético. Debe incluir la evaluación de aspectos psicológicos y de comunicación familiar. El programa PICOGEN del Hospital Clinic de Barcelona para el análisis y asesoramiento genético en demencias es un buen ejemplo de una estrategia integrada capaz de abordar esta nueva situación asistencial en Neurología. Lamentablemente, este programa es una excepción en España y los pacientes con enfermedades neurogenéticas y sus familias no tienen garantizada habitualmente una asistencia adecuada. Conclusiones: El asesoramiento genético es un acto clínico per se, que precisa de un espacio, tiempo y recursos suficientes. Implica una participación multidisciplinar, atención a los aspectos psicológicos y familiares y no se puede llevar a cabo correctamente en el seno de una consulta rutinaria estándar de Neurología. Es necesaria una legislación que garantice la adecuada articulación del asesoramiento genético en nuestro país con criterios de calidad y equidad. Esto incluye la regulación de la formación de los profesionales necesarios, la clarificación de competencias y la dotación de recursos a las instituciones para el desarrollo de estos programas. Abstract: Introduction: The generalization of genetic studies is transforming the practice of Neurology and confronts the clinical departments with new challenges, such as the organization of genetic counseling. The requirement of specialized knowledge, both clinical and molecular, as well as the need for psychological evaluation and family support, especially for predictive testing and reproductive planning, makes a multidisciplinary approach mandatory. Development: The main characteristics of genetic neurodegenerative diseases are the high level of required specialization – since these disorders are often rare and of difficult diagnosis – together with a generally progressive course, unavailability of effective treatment, the issues generated by predictive testing and the interpretation of genetic testing. The aim of genetic counseling is to provide sufficient and objective information for each individual to make their own decision on genetic testing. It must touch upon psychological aspects and family communication. The PICOGEN program from the Clinic Hospital in Barcelona for genetic testing and counseling of dementias is a good example of integrated strategy capable of managing this new clinical scenario in neurology. Unfortunately, this program is an exception in Spain and the patients with neurogenetic disorders and their families usually do not have guaranteed access to an appropriate care. Conclusions: Genetic counseling is a unique clinical activity that requires provision of enough time, space and resources to be developed. It implies multidisciplinary participation, due attention to psychological and family issues, and cannot be carried out adequately in a routine Neurology clinic. Legislation is needed to promote a correct articulation of genetic counseling in our country with guarantee of quality and equity. This includes training of the necessary health professionals, clarification of competences and provision of resources to the institutions for the development of such programs. Palabras clave: Análisis genéticos, Asesoramiento genético, Neurogenética, Legislación, Enfermedades raras, Test predictivos, Keywords: Genetic tests, Genetic counseling, Neurogenetics, Legislation, Rare disorders, Predictive testing

Hereditary ataxias are clinically and genetically heterogeneous neurodegenerative disorders. Although many ataxia genes have been identified, about 50 % of cases await the identification of the genetic cause [1]. High-throughput sequencing, namely whole-exome sequencing (WES), has changed the paradigm of genetic analysis of rare heterogeneous Mendelian disorders [2], and allowed the identification of STUB1 mutations as the cause of autosomal recessive ataxia syndromes [3–7]. We report on clinical and pathological features of a family with spastic ataxia due to novel STUB1

This study aimed to identify the genetic defect in a multigenerational family presenting an autosomal dominant myopathy with histological features of congenital fiber type disproportion. Linkage analysis and genetic sequencing identified, in all affected members of the family, the c.5807A>G heterozygous mutation in MYH7, which encodes the slow/β-cardiac myosin heavy chain. This mutation causes skeletal but not cardiac involvement. Myosin heavy chain expression pattern was also characterized by immunohistochemistry, western blot and q-PCR in muscle biopsies from two patients aged 25 and 62, respectively. While only congenital fiber type disproportion was observed in the younger patient, older patient's biopsy presented aggregates of slow myosin heavy chains, in fiber sub-sarcolemmal region. These clinico-pathologic findings suggest a novel phenotype within the emerging group of hereditary myosin myopathies, which in this family presents typical characteristics of congenital fiber type disproportion in early stages and later evolves to myosin storage myopathy.

Objective To investigate the genetic effect of a new mutation found in exon 17 of the myophosphorylase ( PYGM ) gene as a cause of McArdle disease (also known as type 5 glycogenosis). Patients A Spanish patient with McArdle disease was screened for 3 common mutations in the PYGM gene (R49X, W797R, and G204S), as previously described. The patient was heterozygous for R49X. To find other mutations, the coding sequence of the entire PYGM gene was sequenced. The carrier status of his relatives was also studied. Results A novel rare mutation was found in codon 691 of exon 17. This is an insertion/deletion (indel) and consists simultaneously of a deletion of 2 bases and an insertion of 3 bases (691delCC/insAAA). A restriction analysis was designed to simplify the detection method. Conclusions The 691delCC/insAAA is the third indel described in the PYGM gene. Indels represent 0.95% of the total reported mutations in the Human Gene Mutation Database. The molecular origin of this mutation is not fully understood. These findings point again to the allelic heterogeneity of McArdle disease.