[Diagnostic progress in spinal muscular atrophy]

Progress of diagnostic methods in recognition of spinal muscular atrophy (SMA), the most common degenerative disease of the nervous system in children has been observed in the last years. It has been proved, that all types of SMA, phenotypically variable Werdnig-Hoffman and Kugelberg-Welander diseases are results of homozygous absence of the telomeric copy of SMN gene located on the long arm of chromosome 5; this discovery was very important for mechanisms investigation. Based on the evolution of SMA diagnostic, the results of diagnostic in 18 children hospitalized in the Department of Pediatric Neurology Collegium Medicum of Jagiellonian University are presented. In the years 1995-1997 the basic procedure for confirming the diagnosis of SMA has been muscle biopsy. Molecular studies introduced in 1998 were a chance for confirmation not only classical, but other than three main clinical SMA phenotypes. The molecular analysis performed in children allowed to confirm diagnosis in 7 patients, showing in 5 cases absence of exon 7 of the SMN gene and in 2 children detecting deletions involving SMN and NAIP genes. In the less typical cases the results of molecular analysis were less definite.