Zika virus outbreak in New Caledonia and Guillain-Barré syndrome: a case-control study.

Zika virus (ZIKV) infection has been associated with neurologic disorders including Guillain-Barré syndrome (GBS). In New Caledonia during the ZIKV outbreak (2014-2015), case-control and retrospective studies have been performed to assess the link between ZIKV and GBS. Among the 15 cases included, 33% had evidence of a recent ZIKV infection compared to only 3.3% in the 30 controls involved. All patients were Melanesian, had facial diplegia and similar neurophysiological pattern consistent with acute inflammatory demyelinating polyneuropathy, and recovered well. Furthermore, during the peak of ZIKV transmission, we observed a number of GBS cases higher than the calculated upper limit, emphasizing the fact that ZIKV is now a major trigger of GBS.

RAD51 haploinsufficiency causes congenital mirror movements in humans.

Congenital mirror movements (CMM) are characterized by involuntary movements of one side of the body that mirror intentional movements on the opposite side. CMM reflect dysfunctions and structural abnormalities of the motor network and are mainly inherited in an autosomal-dominant fashion. Recently, heterozygous mutations in DCC, the gene encoding the receptor for netrin 1 and involved in the guidance of developing axons toward the midline, have been identified but CMM are genetically heterogeneous. By combining genome-wide linkage analysis and exome sequencing, we identified heterozygous mutations introducing premature termination codons in RAD51 in two families with CMM. RAD51 mRNA was significantly downregulated in individuals with CMM resulting from the degradation of the mutated mRNA by nonsense-mediated decay. RAD51 was specifically present in the developing mouse cortex and, more particularly, in a subpopulation of corticospinal axons at the pyramidal decussation. The identification of mutations in RAD51, known for its key role in the repair of DNA double-strand breaks through homologous recombination, in individuals with CMM reveals a totally unexpected role of RAD51 in neurodevelopment. These findings open a new field of investigation for researchers attempting to unravel the molecular pathways underlying bimanual motor control in humans.

Neurological disorders in essential thrombocythemia.

Patients with essential thrombocythemia often complain of various subjective neurological symptoms. This prospective study aims to assess their incidence and response to therapy. Among 37 consecutive patients with essential thrombocythemia, 11 presented with neurological symptoms. Among them 4 had thrombotic events, 7 complained of transient or fluctuating subjective symptoms, and one had both. Brain magnetic resonance imagery failed to detect any substratum in patients with subjective symptoms. JAK2V617F mutation was found in 9 of 11 patients with neurological symptoms versus 14 of 26 patients without symptoms. Ten patients received low-dose aspirin for these symptoms: complete resolution was observed in 3, improvement with persisting episodes in 2, and resistance to aspirin in 2 patients, in whom addition of cytoreductive therapy became necessary to resolve those disabling symptoms. In this prospective cohort, 30% of patients with essential thrombocythemia presented neurological symptoms. Aspirin was fully efficient in only 30% of cases. JAK2V617F mutation could be a risk factor for such symptoms.

Acute but transient neurological deterioration revealing adult polyglucosan body disease.

Adult polyglucosan body disease (APBD) is a metabolic disorder usually caused by glycogen branching enzyme (GBE) deficiency. APBD associates progressive walking difficulties, bladder dysfunction and, in about 50% of the cases, cognitive decline. APBD is characterized by a recognizable leukodystrophy on brain MRI. We report here a novel presentation of this disease in a 35-year old woman who presented with an acute deterioration followed by an unexpected recovery. Enzymatic analysis displayed decreased GBE activity in leukocytes. Molecular analyses revealed that only one mutated allele was expressed, bearing a p.Arg515His mutation. This is the first observation reporting acute and reversible neurological symptoms in APBD. These findings emphasize the importance of searching GBE deficiency in patients presenting with a leukodystrophy and acute neurological symptoms mimicking a stroke, in the absence of cardiovascular risk factors.

Upfront association of carboplatin plus pemetrexed in patients with brain metastases of lung adenocarcinoma.

Approximately 10% of patients with non-small cell lung cancer (NSCLC) have brain metastases at the time of diagnosis. When surgical resection is not possible, whole brain radiotherapy is the standard of care, with a cerebral response rate of approximately 30%. We report our experience with an upfront association of carboplatin and pemetrexed (areas under the curve, 5 and 500 mg/m(2), respectively), every 3 weeks, in 30 patients presenting with newly diagnosed brain metastases and NSCLC. Cerebral MRIs were performed every 6-9 weeks. The radiologic response rates were assessed according to Response Evaluation Criteria in Solid Tumors. Overall survival was also determined. Twenty-six patients were evaluable for response, and the objective cerebral response rate (complete and partial response) in the intent-to-treat population was 40% (12 of 30 patients). Event-free survival was 31 weeks, and median overall survival was 39 weeks. The upfront association of carboplatin plus pemetrexed allows simultaneous treatment of cerebral and systemic disease in patients with NSCLC with newly diagnosed brain metastases and appears to be particularly interesting in terms of radiologic response and overall survival. Further clinical studies are warranted.

Congenital mirror movements: a clue to understanding bimanual motor control.

Mirror movements (MM) are involuntary movements of one side of the body that accompany and mirror intentional movements on the opposite side. Physiological MM can occur during normal childhood development, probably owing to corpus callosum immaturity. Pathological congenital MM may be clinically isolated or part of a complex congenital syndrome, including Kallmann syndrome, Klippel-Feil syndrome, and congenital hemiplegia. Congenital isolated MM are usually familial. Recently, heterozygous mutations of the DCC gene, with autosomal dominant inheritance, were shown to cause some cases of MM. The pathogenesis of congenital MM may involve (i) abnormal interhemispheric inhibition between the two motor cortices; (ii) functional alteration of motor planning and motor execution; and/or (iii) abnormal persistence of the ipsilateral corticospinal tract. Fundamental and clinical research is providing novel insights into the complex underlying molecular pathways, and recent experimental work has identified several mechanisms that may mediate the motor network dysfunction. In this review, we analyze clinical, genetic, neurophysiologic, and neuroimaging data on congenital MM, and discuss how this knowledge may improve our understanding of bimanual motor control.