Congenital myasthenic syndrome (CMS) is an inherited neuromuscular disorder caused by defects of several types at the neuromuscular junction. The effects of the disease are similar to Lambert-Eaton Syndrome and myasthenia gravis, the difference being that CMS is not an autoimmune disorder. There are only 600 known family cases of this disorder and it is estimated that its overall frequency in the human population is 1 in 200,000. Types
The types of CMS are classified into three categories: presynaptic, postsynaptic, and synaptic. Presynaptic symptoms include brief stops in breathing, weakness of the eye, mouth, and throat muscles. These symptoms often result in double vision and difficulty chewing and swallowing. Postsynaptic symptoms in infants include severe muscle weakness, feeding and respiratory problems, and delays in the ability to sit, crawl, and walk. Synaptic symptoms include early childhood feeding and respiratory problems, reduced mobility, curvature of the spine, and weakness, which causes a delay in motor milestones. Presentation
The onset of symptoms for all ages may include droopy eyelids. A particular form of postsynaptic CMS (slow-channel CMS) includes severe weakness beginning in infancy or childhood that progresses to respiratory problems, and leads to loss of mobility in adolescence or later life. Mechanisms
Postsynaptic CMS
CMS is associated with genetic defects that affect proteins of the neuromuscular junction. Postsynaptic defects are the most frequent cause of CMS and often result in abnormalities in the acetylcholine receptor (AChR).
Activated FVII binds to endothelial protein C receptor (EPCR), which enhances hemostasis.14 One study showed that eptacog beta binds to EPCR with 25% to 30% more affinity than eptacog alfa, displacing protein C from EPCR binding sites and downregulating activated protein C generation, contributing to its hemostatic effect. Physiology
The main role of factor VII (FVII) is to initiate the process of coagulation in conjunction with tissue factor (TF/factor III). Tissue factor is found on the outside of blood vessels - normally not exposed to the bloodstream. Upon vessel injury, tissue factor is exposed to the blood and circulating factor VII. Once bound to TF, FVII is activated to FVIIa by different proteases, among which are thrombin (factor IIa), factor Xa, IXa, XIIa, and the FVIIa-TF complex itself. The complex of factor VIIa with TF catalyzes the conversion of factor IX and factor X into the active proteases, factor IXa and factor Xa, respectively.The action of the factor is impeded by tissue factor pathway inhibitor (TFPI), which is released almost immediately after initiation of coagulation. Factor VII, which was discovered around 1950, is vitamin K-dependent and produced in the liver. Use of warfarin or similar anticoagulants decreases hepatic synthesis of FVII. Structure
Factor VII shares a common domain architecture with factors IX and X.

Genetics
The gene for factor VII is located on chromosome 13 (13q34). Role in disease
Factor VII deficiency (congenital proconvertin deficiency) is rare and inherited recessively. It presents as a hemophilia-like bleeding disorder. It is treated with recombinant factor VIIa (NovoSeven or AryoSeven).