The review considers the original and published data on the molecular genetic 
basis of proximal spinal muscular atrophy (SMA), the most common monogenic 
neuromuscular disease. The structures of the SMN1 gene and SMN2 pseudogene, 
mutations distorting the SMN1 function, the structure and functions of the Smn 
neurotrophic protein, its role in biogenesis of small nuclear ribonucleoproteins 
(snRNPs), and the principles and prdblems of molecular diagnosis in SMA are 
described. Special consideration is given to the current approaches and 
prospects of gene and cell therapy of SMA, pharmacogenetic methods to correct 
the SMN2 function, and original results of long-term treatment of SMA patients 
with valproic acid drugs.