Is the early-onset torsion dystonia (EOTD) linked to TOR1A gene as frequent as expected in France?

Early onset torsion dystonia are rare movement disorders. Molecular defect is known for only a subgroup, consisting of a unique and recurrent mutation in the TOR1A gene. We undertook a nationwide census of French TOR1A-mutation carriers and the assessment of clinical associated signs. Overall, 53 index cases and 104 relatives were studied and haplotypes linked to the mutation constructed. The previously reported Ashkenazi-Jewish haplotype was found in 11 families with the remainder carrying distinct haplotypes suggesting independent mutation events. This study demonstrates the scarcity of this disease in France with estimated disease frequency of 0.13:100,000 and mutation frequency of 0.17:100,000.

Slowly progressive spinocerebellar ataxia with extrapyramidal signs and mild cognitive impairment (SCA21).

Spinocerebellar ataxia 21 is a slowly progressive and mild ataxia associated with extrapyramidal signs. Affected subjects exhibit a moderate gait and limb ataxia variably associated with akinesia, tremor, rigidity, hyporeflexia, and mild cognitive impairment. The responsible gene has been assigned to a 19 Mbases interval on chromosome 7p in a single French family. No evidence of significant linkage to this locus was found in 21 other families obtained from the EUROSCA consortium. The locus interval contains several candidate genes that could be responsible for the disease. Direct sequencing of NDUFA4, PHF14, KIAA0960, ARLA4, ETV1, DGKB, HDAC9, FERD3L, ITGB8, and SP4 genes were performed, but all the direct mutation analyses were negative excluding pathogenic mutations associated with the disease. Therefore, the gene responsible for SCA21 remains to be identified.

[Interferences by a monoclonal IgM in biochemical analyses: detection and recommendations]. / Interférences par une IgM monoclonale dans un bilan biochimique : détection et recommandations.

We present a case of analytical interference on three parameters (lactate dehydrogenase, uric acid and alkalin phosphatase), caused by a monoclonal IgM, evidenced in a patient with Waldenström disease. Mechanism of interference was probably related to the formation of complexes between paraprotein and lithium heparin, which result in precipitation during clinical chemistry assays, inducing a bias in the results. Management recommendations in case of suspicion of interference in clinical chemistry analysis are detailed. Are discussed for the case report, clinical consequences, possible mechanisms and evolution of interference under treatment, according to the concentration of the monoclonal protein.

[Hypogonadotropic hypogonadism discovered in a patient with cerebellar ataxia]. / Association d'un hypogonadisme hypogonadotrope et d'une ataxie cérébelleuse chez un homme: à propos d'un cas.

We present the case of a male patient who presented progressive cerebellar ataxia since childhood who developed partial hypogonadotropic hypogonadism discovered when searching for a cause of low fecundity. The association of these two entities has been described in several rare syndromes: Homes ataxia, Boucher-Neuhauser syndrome and Richards-Rundle syndrome. The genetic background of these three syndromic associations defined solely on the basis of clinical manifestations remains to be elucidated, leading to uncertain diagnosis. The present case suggests the syndromic entity could be associated with autosomal recessive spinocerebellar ataxia with hypogonadotropic hypogonadism which includes several genotypic entities.

Powerhouse failure and oxidative damage in autosomal recessive spastic ataxia of Charlevoix-Saguenay.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neurodegenerative disease due to mutations in SACS, which encodes sacsin, a protein localized on the mitochondrial surface and possibly involved in mitochondrial dynamics. In view of the possible mitochondrial involvement of sacsin, we investigated mitochondrial activity at functional and molecular level in skin fibroblasts obtained from ARSACS patients. We observed remarkable bioenergetic damage in ARSACS cells, as indicated by reduced basal, adenosine triphosphate (ATP)-linked and maximal mitochondrial respiration rate, and by reduced respiratory chain activities and mitochondrial ATP synthesis. These phenomena were associated with increased reactive oxygen species production and oxidative nuclear DNA damage. Our results suggest that loss of sacsin is associated with oxidative stress and mitochondrial dysfunction, and thus highlight a novel mechanism in the pathogenesis of ARSACS. The involvement of mitochondria and oxidative stress in disease pathogenesis has been described in a number of other neurodegenerative diseases. Therefore, on the basis of our findings, which suggest a potential therapeutic role for antioxidant agents, ARSACS seems to fall within a larger group of disorders.

Clinical features and genetic analysis of a new form of spinocerebellar ataxia.

BACKGROUND: The autosomal dominant cerebellar ataxias (ADCA) are a clinically heterogeneous group of disorders. The mutations for SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, and SCA-12 are identified and caused by an expansion of a CAG or a CTG repeat sequence of these genes. Six additional loci for SCA4, SCA5, SCA-10, SCA-11, SCA-13, and SCA-14 are mapped. The growing heterogeneity of the autosomal dominant forms of these diseases shows that the genetic etiologies of at least 20% of ADCA have yet to be elucidated. METHODS: The authors ascertained and clinically characterized a four-generation pedigree segregating an autosomal dominant phenotype for SCA. Direct mutation analysis, repeat expansion detection analysis, and linkage analysis for all known SCA loci were performed. RESULTS: Direct mutational analysis excluded SCA1, 2, 3, 6, 7, 8, and 12; genetic linkage analysis excluded SCA4, 5,10, 11, 13, and 14, giving significant negative lod scores. Examination of the family showed that all affected members had gait ataxia and akinesia with variable features of dysarthria, hyporeflexia, and mild intellectual impairment. Eye movements were normal. Head MRI showed atrophy of the cerebellum without involvement of the brainstem. In 10 parent-child pairs, median onset occurred 10.5 years earlier in offspring than in their parents, suggesting anticipation. CONCLUSION: This family is distinct from other families with SCA and is characterized by cerebellar ataxia and extrapyramidal signs.

Simple nonisotopic assays for detection of (CAG)n repeats expansions associated with seven neurodegenerative disorders.

To date, eight neurodegenerative diseases, including Huntington's disease, dentatorubral-pallidoluysian atrophy, spinal and bulbar muscular atrophy, and spinocerebellar ataxia (SCA) types 1, 2, 3, 6, and 7, have been proven to be caused by an expanded trinucleotide repeat (CAG)n located within a specific gene for each of these diseases. Except in SCA 6, the CAG repeat is present in approximately 7 to 35 copies in the normal population, whereas patients have CAG expansions of 40 to approximately 75 repeats. Sizing of the repeat length enables molecular diagnosis in affected patients and presymptomatic persons carrying a mutated allele. A molecular protocol for the diagnosis of these diseases was developed based on polymerase chain reaction, denaturing polyacrylamide gel electrophoresis and staining with silver nitrate, and adapted to each disease. This simple and rapid method gives a sensitivity of detection equal to current procedures but avoids isotopic manipulations. Therefore, shorter turnaround time, decreased cost per sample, and simplified screening of these neurodegenerative diseases by PCR-based assays may be attainable using this protocol.

[Guidelines for the point-of-care testing post-examination phase management]. / Recommandations pour la maîtrise de la phase post-analytique des examens de biologie médicale délocalisés.

For point-of-care-testing (POCT), the French regulation on medical biology states allows a unique situation where a delayed validation of results is possible. This paper proposes guidelines to organize POCT post-analytical phase in agreement with the local regulation and ISO 22870 requirements. In the first part, organization of POCT validation is detailed (since analysis results reading by the physician until validation of results by the medical biologist and their integration into the patient record). In a second part, elements to include in POCT presentation of results are discussed and a model is proposed.

[Guidelines for selection and implementation of a point-of-care testing device according to the EN ISO 22870 and French regulation]. / Recommandations pour le choix et la mise en place d'un dispositif de biologie médicale délocalisé.

Implementation is the main step of the point-of-care testing (POCT) device installation process to comply with EN ISO 22870. The multidisciplinary POCT management group is in charge to align that process with the standards but also with the French regulation (ordinance 2010-49 of 13 January 2010) which authorizes POCT only in case of urgent therapeutic decisions. This article defines two reports to be prepared during the deployment of a POCT device : a report that justifies the use of a POCT device, taking into account a risk-benefit analysis and a report that justifies the choice of the device including proofs of conformity of its installation.

Real time RT-PCR shows correlation between retinoid-induced apoptosis and NGF-R mRNA levels.

Neurotrophins and retinoic acid have a critical role in the differentiation and the survival of neurons. All-trans-, 9-cis-retinoic acid (10(-6) M) or NGF (50-100 ng/ml) induced morphologic differentiation and inhibited cell growth in SH-SY5Y neuroblastoma cells after 7 days of culture. Continuous treatment of undifferentiated cells with all-trans- or 9-cis-retinoic (10(-6) M) did not induce apoptosis, whereas NGF-differentiated cells showed dramatic apoptosis after 2 to 4 days of retinoic acid treatment as evidenced by TUNEL reaction and flow cytometry analysis following propidium iodide staining. Addition of Ro41-5253 blocked all-trans-retinoic-induced apoptosis, suggesting that the apoptotic signaling pathway was mediated by RARs. The effects of all-trans- or 9-cis-retinoic acid on the expression of NGF receptors was evaluated using real-time fluorescence reverse transcription-PCR. A slight transient increase in the expression of p75(NGFR) mRNA was observed by 2 to 4 h after retinoid treatment of undifferentiated cells, whereas a larger increase in the expression of both TrkA and p75(NGFR) mRNA up to threefold the basal level, was observed by 2 to 6 h after retinoid treatment of NGF-differentiated cells. Our results suggest that NGF-differentiated cells may be more susceptible to retinoid-induced apoptosis than undifferentiated cells.

The first identified French family with dentatorubral-pallidoluysian atrophy.

We report the first French family with dentatorubral-pallidoluysian atrophy (DRPLA) in which three members, a 36-year-old woman (proband), her 34-year-old sister, and 14-year-old brother were affected. There was no family history of DRPLA and their father presented at age 66 with pes cavus but without any other neurologic symptoms. Molecular analysis of the DRPLA gene from blood leukocytes showed CAG repeat sizes to be 68/16 in the proband, 62/15 in her father, and 16/16 in her mother. This study provides support for the variable clinical presentation of this disease with incomplete penetrance in the father and demonstrates that DRPLA can be observed in the French Caucasian population.

Absence of unidentified CAG repeat expansion in patients with Huntington's disease-like phenotype.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by an expanded (CAG)n repeat on the huntingtin gene. It is characterised by motor, psychiatric and cognitive disturbances. Diagnosis can be confirmed by direct genetic testing, which is highly sensitive and specific and is now considered definitive. This study focused on 21 patients presenting with a clinical phenotype showing strong similarity to HD, but who do not have an expanded CAG in the huntingtin gene. However, other possible diagnoses could be evoked for most of them. Seven patients (3.5% of our cohort) could be considered as phenocopies of HD with no alternative diagnosis. Samples were screened for other triplet repeat diseases with similar presentation (DRPLA, SCA-1, SCA-2, SCA-3, SCA-6, and SCA-7) and were all negative. The repeat expansion detection technique (RED) was used to detect uncloned CAG repeat expansions and samples were also analysed by polymerase chain reaction for expansions of the polymorphic CAG-ERDA-1 and CTG18.1 trinucleotide repeats. RED expansion (>40 repeats) was detected in only one patient. The results suggest that unstable CAG/CTG repeat expansions corresponding to known or unknown sequences are not involved in the aetiology of HD-like disorders. It is hypothesised that some of these phenocopies could correspond to mutations in other unidentified genes with other unstable repeats (different from CAG) or in unknown genes with other mutations.

Genetic polymorphisms adjacent to the CAG repeat influence clinical features at onset in Huntington's disease.

OBJECTIVES: To evaluate possible influences of CCG and delta2642 glutamic acid polymorphisms adjacent to the (CAG)n trinucleotide repeat in Huntington's disease gene IT15 on some clinical features (age and symptoms) at onset. METHODS: 84 patients and a control group of 68 unaffected relatives were studied. Patients all belonged to a group of affected persons tested for molecular confirmation of Huntington's disease. The length of the CAG repeat sequence in the IT15 gene and the adjacent CCG and delta2642 polymorphisms were determined by quantitative polymerase chain reaction. RESULTS: Two intragenic polymorphisms were studied: (CCG)n and delta2642 glutamic acid. Patients were classified firstly according to the size of the CCG rich segment adjacent to the CAG repeat into genotype groups CCG 7/7, 7/8, 7/9, 7/10, and 10/10 and then according to delta2642 polymorphism into genotype groups A/A (absence of the delta2642 deletion), A/B, and B/B (presence of the delta2642 deletion in respectively one and two alleles). The presence of delta2642 mutation was associated with a significant decrease in age at onset, although there was no significant increase in CAG size. A good correlation was found between the (CAG)n trinucleotide repeat size and the age at onset in patients with genotype AA (r2=0.72). Within patients of the A/B genotype group however, a significant correlation was found but with a drop of the r2 value to 0.44. No association was found between age at onset and the CCG polymorphism. Although an increased percentage of patients within the A/A genotype group had a neurological onset, we found no overall significant association between CCG or delta2642 polymorphisms and the nature of symptoms at onset. CONCLUSIONS: The delta2642 glutamic acid polymorphism did not affect CAG repeat size nor the nature of symptoms at onset but seems to influence the age at onset in patients with Huntington's disease.