Hereditary diffuse leukoencephalopathy with axonal spheroids: More than just a rare disease.

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a progressive white matter disease with a wide range of clinical symptoms including dementia, behavioral changes, seizures, pyramidal signs, ataxia, and parkinsonism.(1-3) Affected individuals develop symptoms in their early 40s with an average survival time of 10 years. HDLS is inherited as an autosomal dominant trait. Recently, mutations in the colony-stimulating factor 1 receptor gene (CSF-1R) were identified as the genetic cause of HDLS.(4) White matter lesions, easily demonstrated on MRI studies, involve predominantly the frontal lobes and corpus callosum with subsequent cortical atrophy. MRI abnormalities are present prior to symptom onset.(5,6) Histopathology shows widespread myelin and axon destruction with axonal dilations termed spheroids, as well as pigmented macrophages.

A clinical pattern-based etiological diagnostic strategy for sensory neuronopathies: a French collaborative study.

Sensory neuronopathies (SNNs) encompass paraneoplastic, infectious, dysimmune, toxic, inherited, and idiopathic disorders. Recently described diagnostic criteria allow SNN to be differentiated from other forms of sensory neuropathy, but there is no validated strategy based on routine clinical investigations for the etiological diagnosis of SNN. In a multicenter study, the clinical, biological, and electrophysiological characteristics of 148 patients with SNN were analyzed. Multiple correspondence analysis and logistic regression were used to identify patterns differentiating between forms of SNNs with different etiologies. Models were constructed using a study population of 88 patients and checked using a test population of 60 cases. Four patterns were identified. Pattern A, with an acute or subacute onset in the four limbs or arms, early pain, and frequently affecting males over 60 years of age, identified mainly paraneoplastic, toxic, and infectious SNN. Pattern B identified patients with progressive SNN and was divided into patterns C and D, the former corresponding to patients with inherited or slowly progressive idiopathic SNN with severe ataxia and electrophysiological abnormalities and the latter to patients with idiopathic, dysimmune, and sometimes paraneoplastic SNN with a more rapid course than in pattern C. The diagnostic strategy based on these patterns correctly identified 84/88 and 58/60 patients in the study and test populations, respectively.

Early co-occurrence of a neurologic-psychiatric disease pattern in Niemann-Pick type C disease: a retrospective Swiss cohort study.

BackgroundNiemann-Pick disease type C (NP-C) is a rare autosomal recessive disorder of lysosomal cholesterol transport. The objective of this retrospective cohort study was to critically analyze the onset and time course of symptoms, and the clinical diagnostic work-up in the Swiss NP-C cohort.MethodsClinical, biochemical and genetic data were assessed for 14 patients derived from 9 families diagnosed with NP-C between 1994 and 2013. We retrospectively evaluated diagnostic delays and period prevalence rates for neurological, psychiatric and visceral symptoms associated with NP-C disease. The NP-C suspicion index was calculated for the time of neurological disease onset and the time of diagnosis.ResultsThe shortest median diagnostic delay was noted for vertical supranuclear gaze palsy (2y). Ataxia, dysarthria, dysphagia, spasticity, cataplexy, seizures and cognitive decline displayed similar median diagnostic delays (4¿5y). The longest median diagnostic delay was associated with hepatosplenomegaly (15y). Highest period prevalence rates were noted for ataxia, dysarthria, vertical supranuclear gaze palsy and cognitive decline. The NP-C suspicion index revealed a median score of 81 points in nine patients at the time of neurological disease onset which is highly suspicious for NP-C disease. At the time of diagnosis, the score increased to 206 points.ConclusionA neurologic-psychiatric disease pattern represents the most characteristic clinical manifestation of NP-C and occurs early in the disease course. Visceral manifestation such as isolated hepatosplenomegaly often fails recognition and thus highlights the importance of a work-up for lysosomal storage disorders. The NP-C suspicion index emphasizes the importance of a multisystem evaluation, but seems to be weak in monosymptomatic and infantile NP-C patients.

Carriers of the fragile X mental retardation 1 (FMR1) premutation allele present with increased levels of cytokine IL-10.

BACKGROUND: Fragile X-associated tremor/ataxia syndrome (FXTAS) is an inherited late-onset neurodegenerative disorder, characterized both by neurological and cognitive deficits. It is caused by the expansion of CGG repeats (55 to 200 repeats) in the noncoding region of the fragile X mental retardation 1 (FMR1) gene. Abnormal immunological patterns are often associated with neurodegenerative disorders and implicated in their etiology. We therefore investigated the immune status of FXTAS patients, which had not been assessed prior to this study. METHOD: Peripheral blood mononuclear cells (PBMCs) were collected from 15 asymptomatic FMR1 premutation carriers and 20 age-matched controls. Concentrations of three cytokines (IL-6, IL-8, IL-10) were measured in PBMC supernatants using ELISA assays. RESULTS: We found a significant increase in the concentration of the major anti-inflammatory cytokine IL-10 in supernatants of PBMCs derived from premutation carriers, when compared with controls (P = 0.019). This increase correlated significantly with the number of CGG repeats (P = 0.002). CONCLUSIONS: Elevated IL-10 levels were observed in all premutation carriers, before appearance of the classical neurological symptoms; therefore, IL-10 may be one of the early biomarkers of FXTAS.

Calpastatin-mediated inhibition of calpains in the mouse brain prevents mutant ataxin 3 proteolysis, nuclear localization and aggregation, relieving Machado-Joseph disease.

Machado-Joseph disease is the most frequently found dominantly-inherited cerebellar ataxia. Over-repetition of a CAG trinucleotide in the MJD1 gene translates into a polyglutamine tract within the ataxin 3 protein, which upon proteolysis may trigger Machado-Joseph disease. We investigated the role of calpains in the generation of toxic ataxin 3 fragments and pathogenesis of Machado-Joseph disease. For this purpose, we inhibited calpain activity in mouse models of Machado-Joseph disease by overexpressing the endogenous calpain-inhibitor calpastatin. Calpain blockage reduced the size and number of mutant ataxin 3 inclusions, neuronal dysfunction and neurodegeneration. By reducing fragmentation of ataxin 3, calpastatin overexpression modified the subcellular localization of mutant ataxin 3 restraining the protein in the cytoplasm, reducing aggregation and nuclear toxicity and overcoming calpastatin depletion observed upon mutant ataxin 3 expression. Our findings are the first in vivo proof that mutant ataxin 3 proteolysis by calpains mediates its translocation to the nucleus, aggregation and toxicity and that inhibition of calpains may provide an effective therapy for Machado-Joseph disease.

Prevalence of subfoveal nodules in Coat's disease

Purpose:Coats' disease is a non-hereditary condition characterized by idiopathic retinal telangiectasia, and exudative retinopathy. Although the exudation often spreads from the main areas of telangiectasia, there is a preferential accumulation of exudation in the macular area in Coats' disease. A subfoveal nodule has usually been described in the context of resolution of macular exudates after treatment of peripheral retinal telangiectasis. Nevertheless, a recent reports stressed out an uncommon prominent subfoveal nodule with peripheral exudates as initial presentation of Coats'disease. The purpose of this study was to report the prevalence of this presentation in a cohort of patients. Methods:All consecutive patients with Coats' disease referred to the Jules Gonin Eye Hospital between January 1979 and July 2006 were included. All charts were screened for a clear cut subfoveal circular lesion on fundus photographies at initial presentation. Results:95 patients suffering of Coat's disease were enrolled. 33 out of 95 patients had subtotal or total exudative retinal detachment, which impeded macular examination. 14 out of 62 (22.6%) resting patients presented with a clear cut prominent circular subfoveal lesion at initial presentation. All patients had unilateral disease. Mean age was 5.6 ± 3.5 year old at initial presentation. There were 4 females and 10 males. Pigmentation and size of the nodule were not homogenous. Mean diameter was 1.1 ± 0.5 optic disc diameter. Conclusions:The present study shows that subfoveal nodule is not such a rare primary presentation of Coats' disease in contrast to what it has been previously reported in the literature. Thus the initial finding of prominent subfoveal nodule associated with peripheral retinal findings made the diagnosis of Coats' disease highly likely.Physicians should be aware that a proeminent subfoveal nodule is a common initial presentation of Coats' disease as it can be confused clinically with Retinoblastoma.

Lack of the alanine-serine-cysteine transporter 1 causes tremors, seizures, and early postnatal death in mice.

The Na(+)-independent alanine-serine-cysteine transporter 1 (Asc-1) is exclusively expressed in neuronal structures throughout the central nervous system (CNS). Asc-1 transports small neutral amino acids with high affinity especially for D-serine and glycine (K(i): 8-12 microM), two endogenous glutamate co-agonists that activate N-methyl-D-aspartate (NMDA) receptors through interacting with the strychnine-insensitive glycine binding-site. By regulating D-serine (and possibly glycine) levels in the synaptic cleft, Asc-1 may play an important role in controlling neuronal excitability. We generated asc-1 gene knockout (asc-1(-/-)) mice to test this hypothesis. Behavioral phenotyping combined with electroencephalogram (EEG) recordings revealed that asc-1(-/-) mice developed tremors, ataxia, and seizures that resulted in early postnatal death. Both tremors and seizures were reduced by the NMDA receptor antagonist MK-801. Extracellular recordings from asc-1(-/-) brain slices indicated that the spontaneous seizure activity did not originate in the hippocampus, although, in this region, a relative increase in evoked synaptic responses was observed under nominal Mg(2+)-free conditions. Taken together with the known neurochemistry and neuronal distribution of the Asc-1 transporter, these results indicate that the mechanism underlying the behavioral hyperexcitability in mutant mice is likely due to overactivation of NMDA receptors, presumably resulting from elevated extracellular D-serine. Our study provides the first evidence to support the notion that Asc-1 transporter plays a critical role in regulating neuronal excitability, and indicate that the transporter is vital for normal CNS function and essential to postnatal survival of mice.

RNA interference mitigates motor and neuropathological deficits in a cerebellar mouse model of machado-joseph disease.

Machado-Joseph disease or Spinocerebellar ataxia type 3 is a progressive fatal neurodegenerative disorder caused by the polyglutamine-expanded protein ataxin-3. Recent studies demonstrate that RNA interference is a promising approach for the treatment of Machado-Joseph disease. However, whether gene silencing at an early time-point is able to prevent the appearance of motor behavior deficits typical of the disease when initiated before onset of the disease had not been explored. Here, using a lentiviral-mediated allele-specific silencing of mutant ataxin-3 in an early pre-symptomatic cerebellar mouse model of Machado-Joseph disease we show that this strategy hampers the development of the motor and neuropathological phenotypic characteristics of the disease. At the histological level, the RNA-specific silencing of mutant ataxin-3 decreased formation of mutant ataxin-3 aggregates, preserved Purkinje cell morphology and expression of neuronal markers while reducing cell death. Importantly, gene silencing prevented the development of impairments in balance, motor coordination, gait and hyperactivity observed in control mice. These data support the therapeutic potential of RNA interference for Machado-Joseph disease and constitute a proof of principle of the beneficial effects of early allele-specific silencing for therapy of this disease.

Outcome of severe unilateral cerebellar hypoplasia.

Aim: Complete or subtotal absence of one cerebellar hemisphere is exceptional; only single cases have been described. We aimed to assess the long-term outcome in children with severe unilateral cerebellar hypoplasia (UCH). Method: As part of a retrospective study we describe neuroimaging features, clinical findings, and cognitive outcomes of seven children with UCH (five males, two females; age at first magnetic resonance imaging [MRI]: median 1y 3mo, range 9d-8y 10mo; age at latest follow-up: median 6y 6mo, range 2y 3mo-14y 11mo). Results: One child had abnormalities on prenatal MRI at 21 weeks' gestation. The left cerebellar hemisphere was affected in five children, and the right hemisphere in two children. The vermis was involved in five children. The volume of the posterior fossa was variable. At the latest follow-up, neurological findings included truncal ataxia and muscular hypotonia in five children, limb ataxia in three patients, and head nodding in two patients. Three children had learning disability*, five had speech and language disorders, and one had a severe behavioural disorder. Interpretation: Severe UCH is a residual change after a disruptive prenatal cerebellar insult, most likely haemorrhagic. The outcome is variable, ranging from almost normal development to marked developmental impairment. Ataxia is a frequent but not a leading sign. It seems that involvement of the cerebellar vermis is often, but not consistently, associated with a poorer cognitive outcome, whereas an intact vermis is associated with normal outcome and no truncal ataxia.

Sudden unexpected death in an infant with L-2-hydroxyglutaric aciduria.

Inherited metabolic disorders are the cause of a small but significant number of sudden unexpected deaths in infancy. We report a girl who suddenly died at 11 months of age, during an intercurrent illness. Autopsy showed spongiform lesions in the subcortical white matter, in the basal ganglia, and in the dentate nuclei. Investigations in an older sister with developmental delay, ataxia, and tremor revealed L-2-hydroxyglutaric aciduria and subcortical white matter changes with hyperintensity of the basal ganglia and dentate nuclei at brain magnetic resonance imaging. Both children were homozygous for a splice site mutation in the L2HGDH gene. Sudden death has not been reported in association with L-2-hydroxyglutaric aciduria so far, but since this inborn error of metabolism is potentially treatable, early diagnosis may be important.

Single nucleotide polymorphisms, apoptosis, and the development of severe late adverse effects after radiotherapy.

PURPOSE: Evidence has accumulated in recent years suggestive of a genetic basis for a susceptibility to the development of radiation injury after cancer radiotherapy. The purpose of this study was to assess whether patients with severe radiation-induced sequelae (RIS; i.e., National Cancer Institute/CTCv3.0 grade, > or =3) display both a low capacity of radiation-induced CD8 lymphocyte apoptosis (RILA) in vitro and possess certain single nucleotide polymorphisms (SNP) located in candidate genes associated with the response of cells to radiation. EXPERIMENTAL DESIGN: DNA was isolated from blood samples obtained from patients (n = 399) included in the Swiss prospective study evaluating the predictive effect of in vitro RILA and RIS. SNPs in the ATM, SOD2, XRCC1, XRCC3, TGFB1, and RAD21 genes were screened in patients who experienced severe RIS (group A, n = 16) and control subjects who did not manifest any evidence of RIS (group B, n = 18). RESULTS: Overall, 13 and 21 patients were found to possess a total of <4 and > or =4 SNPs in the candidate genes. The median (range) RILA in group A was 9.4% (5.3-16.5) and 94% (95% confidence interval, 70-100) of the patients (15 of 16) had > or =4 SNPs. In group B, median (range) RILA was 25.7% (20.2-43.2) and 33% (95% confidence interval, 13-59) of patients (6 of 18) had > or =4 SNPs (P < 0.001). CONCLUSIONS: The results of this study suggest that patients with severe RIS possess 4 or more SNPs in candidate genes and low radiation-induced CD8 lymphocyte apoptosis in vitro.

An overview of L-2-hydroxyglutarate dehydrogenase gene (L2HGDH) variants: a genotype-phenotype study.

L-2-Hydroxyglutaric aciduria (L2HGA) is a rare, neurometabolic disorder with an autosomal recessive mode of inheritance. Affected individuals only have neurological manifestations, including psychomotor retardation, cerebellar ataxia, and more variably macrocephaly, or epilepsy. The diagnosis of L2HGA can be made based on magnetic resonance imaging (MRI), biochemical analysis, and mutational analysis of L2HGDH. About 200 patients with elevated concentrations of 2-hydroxyglutarate (2HG) in the urine were referred for chiral determination of 2HG and L2HGDH mutational analysis. All patients with increased L2HG (n=106; 83 families) were included. Clinical information on 61 patients was obtained via questionnaires. In 82 families the mutations were detected by direct sequence analysis and/or multiplex ligation dependent probe amplification (MLPA), including one case where MLPA was essential to detect the second allele. In another case RT-PCR followed by deep intronic sequencing was needed to detect the mutation. Thirty-five novel mutations as well as 35 reported mutations and 14 nondisease-related variants are reviewed and included in a novel Leiden Open source Variation Database (LOVD) for L2HGDH variants (http://www.LOVD.nl/L2HGDH). Every user can access the database and submit variants/patients. Furthermore, we report on the phenotype, including neurological manifestations and urinary levels of L2HG, and we evaluate the phenotype-genotype relationship.

Ophthalmic features of PLA2G6-related paediatric neurodegeneration with brain iron accumulation.

BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA) refers to genetically heterogenous paediatric neurodegenerative disorders characterised by basal ganglia iron deposition. One major cause is recessive mutations in the PLA2G6 gene. While strabismus and optic nerve pallor have been reported for PLA2G6-related disease, the ophthalmic phenotype is not carefully defined. In this study we characterise the ophthalmic phenotype of PLA2G6-related NBIA. METHODS: Prospective cohort study. RESULTS: The eight patients were 4-26 years old when examined. All had progressive cognitive and motor regression first noted between 9 months and 6 years of age that typically first manifested as difficulty walking (ataxia). Ophthalmic examination was sometimes limited by cognitive ability. Four of eight had exotropia, 7/7 bilateral supraduction defect, 5/7 poor convergence, 6/8 saccadic pursuit, 4/8 saccadic intrusions that resembled square-wave jerks, and 8/8 bilateral optic nerve head pallor. All patients lacked Bell phenomenon. CONCLUSIONS: Upgaze palsy, although not a previously reported finding, was confirmed in all patients (except in one for whom assessment could not be performed) and thus can be considered part of the phenotype in children and young adults. Other frequent findings not previously highlighted were abnormal convergence, saccadic pursuit, and saccadic intrusions. Optic nerve head pallor and strabismus, previously reported findings in the disease, were found in 100% and 50% of our cohort, respectively, and the strabismus in our series was always exotropia. Taken together, these clinical findings may be helpful in distinguishing PLA2G6-related neurodegeneration from the other major cause of NBIA, recessive PANK2 mutations.

Séquelles radio-induites et tests prédictifs [Radiation-induced sequelae: toward an individual profile]

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the targeted volume. Nevertheless, the dose delivery is limited by the tolerated dose of the surrounding healthy tissues. Two different side effects (acute and late) can occur during and after radiotherapy. Of particular interest are the radiation-induced sequelae due to their irreversibility and the potential impact on daily quality of life. In a population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists. In the hypothesis that genetic is involved in this area of research, lymphocytes seem to be the tissue of choice due to easy accessibility. Recently, low percentage of CD4 and CD8 lymphocyte apoptosis were shown to be correlated with high grade of sequelae. In addition, recent data suggest that patients with severe radiation-induced late side effects possess four or more SNP in candidate genes (ATM, SOD2, TGFB1, XRCC1 et XRCC3) and low radiation-induced CD8 lymphocyte apoptosis in vitro.