oa Congenital Muscular Dystrophy and Neuromuscular Disorders: An Overview

The muscle unit structure has been used to classify neuromuscular disorders (NMDs) according to the site of involvement. The four main muscle unit components involve the: 1) Neuronal Anterior Horn Cell (AHC). 2) Nerve Fiber (axon) transmitting the signal from the AHC to the skeletal muscle fibers. 3) Neuromuscular junction (NMJ) (the cleft between nerve fiber’s endings and muscle sarcolemma membrane). 4) Contractile unit (muscle belly that contains several muscle bundles; every bundle has 100-1000 muscle fibers). The myofibrils (muscle fibers) are the most complex component in terms of the extensive number of proteins that code for the myofibers’ proteins and molecules. Spinal muscular atrophy (SMA) presents the well-known AHC-related muscular diseases. The group of axons-related NMDs (Neuropathy), called “Charcot Marie Tooth (CMT) diseases”, involves several subtypes and are of different inheritance pattern. The NMJ-related NMDs is collectively named as “Myathenias”, of which are the congenital myathenic syndromes. The muscle tissues (myofibrils) are associated with the most extensive group of muscle diseases. Congenital muscular dystrophies (CMDs) and congenital myopathies are primary muscle diseases that appear since birth and run progressive severe courses. Neuromyology is currently a neurology sub-specialization that is highly effective in better clinical identification of such significant genetically heterogeneous and clinically overlapping groups of NMDs and CMDs. The advances in sequencing technologies have contributed towards uncovering the widerange of genetic heterogeneity in NMDs. To date, over 600 genes were characterized in association with congenital myopathies, dystrophies, and NMDs.

The future is holding truly promising cures for NMDs’ patients, through the emerging gene therapies, however its extremely high cost challenges the possibility for large-scale applications.