Myopathy in the York Platelet Syndrome: An Underrecognized Complication

York Platelet Syndrome (YPS) is a calcium channelopathy caused by gain of function in STIM1, a gene which acts as a calcium sensor. It is characterized by platelet abnormalities and muscle weakness. Medical literature emphasizes the hematologic aspects of the cases with few data of the neuromuscular and neuropathologic evaluation. We present a patient with YPS whose myopathy was the most prominent aspect. She presented around 2 years of age with proximal weakness and easy bruisability. YPS was diagnosed in the infant at 16 months of age at the National Institutes of Health. Muscle biopsy demonstrated a severe chronic myopathy. Rimmed vacuoles and tubular aggregates were noted. Although YPS is rare, the combination of a congenital myopathy with thrombocytopenia may facilitate the diagnosis and enable further insights into the disease.

Abstract 111: Cdk5 is Associated in Cardiac Calcium Channelopathy

Cardiac calcium channels play important roles in hearts. Mutations in Ca V 1.2 channels are associated with cardiac arrhythmias including long QT syndrome type 8 (LQTS8). Using human induced pluripotent stem cells (iPSCs) to generate human cardiomyocytes from LQTS8 patients, we reported that the G406R mutation (LQTS8, Timothy syndrome) affected channel inactivation, action potentials and calcium handling in human cardiomyocytes. We found that roscovitine, a cyclin-dependent kinase (CDK) inhibitor, rescued the phenotypes in LQTS8 cardiomyocytes. However, how roscovitine restores the physiological functions in the patient cardiomyocytes remains unclear. Our recent results using roscovitine analogs and CDK inhibitors suggested that CDK5 is involved in the molecular bases of LQTS8. We found that dominant negative forms and shRNA of CDK5 alleviated the phenotypes of the LQTS8 cardiomyocytes and that the expressions of phosphorylated ERK, EGR1 and CDK5R1, a CDK5 activator, significantly increased in the patient cardiomyocytes. The results reveal that calcium overload due to affected Ca V 1.2 inactivation activates ERK/EGR1 pathway, resulting in increased expression of CDK5R1. Biochemical assays supported a direct binding and phosphorylation of Ca V 1.2 channels by CDK5. Overall, the results demonstrated that CDK5 regulates Ca V 1.2 channels and that CDK5 inhibition could be a new therapeutic for LQTS8. This study demonstrates the role of ERK/EGR1/CDK5 in pathogenesis of cardiac arrhythmia. The outcomes of this study provide new insights into Ca V 1.2 channel regulation.

New migraine preventive options: an update with pathophysiological considerations

BACKGROUND: The pharmacological treatment of migraine may be acute or preventive. Frequent, severe and long-lasting migraine attacks require prophylaxis. Multiple threads of research over the last 15 years have led to the concept that migraine is generated from a hyperexcitable brain. A variety of causes for hyperexcitability of the brain in migraine have been suggested. These causes include low cerebral magnesium levels, mitochondrial abnormalities, dysfunctions related to increased nitric oxide or the existence of a P/Q type calcium channelopathy. The better knowledge about migraine pathophisiology led us to discuss new treatment options. OBJECTIVES: The aim of the present study is to present an evidence-based review of some new drugs or some agents that even though available for a long time, are not frequently used. METHODS/RESULTS: We present a review of anticonvulsants with various mechanisms of action such as lamotrigine, gabapentin, topiramate, tiagabine, levetiracetam and zonisamide. We also review natural products, like riboflavin and magnesium, botulinum toxin A, a specific CGRP antagonist and the anti-asthma medication montelukast, with pathophysiological discussion. CONCLUSIONS: We aimed to present an update of newer or less frequently used preventive migraine therapies, drugs that might reduce the burden and the costs of a disease that should be considered as a public health problem all around the world.