SMN1 and proximal spinal muscular atrophy: Russian test systems, like “IMMUNO-BIT” (for quantitative detection of TREC and KREC DNA in children up to 18 years of age) and “TK-SMA”, with an additional channel for qualitative detection of SMN1 gene deletion associated with spinal muscular atrophy (used as part of extended neonatal screening) have been developed and registered in Russia.