To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases, hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth Type 2 (CMT2). In contrast, ALS associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss of function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.

Axonal GBS is pathophysiologically characterised not only by axonal degeneration but also by reversible conduction failure at the axolemma of the Ranvier node. The lack of distinction among demyelinating conduction block, reversible conduction failure and length-dependent compound muscle action potential amplitude reduction may fallaciously classify patients with axonal GBS as having AIDP. Serial electrophysiological studies are mandatory for proper diagnosis of GBS subtypes and the identification of pathophysiological mechanisms of muscle weakness. More reliable electrodiagnostic criteria taking into consideration the reversible conduction failure pattern should be devised.

Acute motor neuropathy with normal or brisk tendon reflexes, conduction block, and fast recovery appears to be a variant of Guillain-Barré syndrome. Conduction block may result from immune-mediated conduction failure at the nodes of Ranvier without demyelination.

Zn 2+ is a potently toxic cation involved in the neuronal injury observed in cerebral ischemia, epilepsy, and brain trauma. Toxic Zn 2+ accumulation may result from either trans-synaptic Zn 2+ movement and/or cation mobilization from intracellular sites. To gain entry to the cytosol, Zn 2+ can flux through glutamate receptor-associated channels, voltage-sensitive calcium channels, or Zn 2+ -sensitive membrane transporters, while metallothioneins and mitochondria provide sites of intracellular Zn 2+ release. Intracellular Zn 2+ homeostasis is sensitive to patho-physiological environmental changes, such as acidosis, inflammation and oxidative stress. The mechanisms by which Zn 2+ exerts its neurotoxicity include mitochondrial and extra-mitochondrial production of reactive oxygen species and disruption of metabolic enzymatic activity, ultimately leading to activation of apoptotic and/or necrotic processes. Beside acute neuronal injury, an exciting new area of investigation is offered by the role of Zn 2+ dysmetabolism in Alzheimer's disease as the cation acts as a potent trigger for Aβ aggregation and plaque formation. Finally, recent findings suggest that alteration of Zn 2+ homeostasis might also be a critical contributor to aging-related neurodegenerative processes. Thus, multiple evidence suggest that modulation of intracellular and extracellular Zn 2+ might be an important therapeutical target for the treatment of a vast array of neurological conditions ranging from stroke to Alzheimer's disease.