Spinal muscular atrophy (SMA) is a neuromuscular disease characterized by weakness and atrophy of proximal muscles. Despite the fact that the disease transmission suggests an autosomal recessive trait, the wide spectrum of clinical manifestations indicates that other genes may contribute to the SMA phenotype. To identify possible modifier genes, the aim of our study was to investigate the relationship between BamH1 perlecan gene polymorphism and SMA type I, the classical severe form of the disease. We genotyped 40 patients with SMA type I disease and 50 subjects without personal or heredo-colateral neuromuscular problems, using the polymerase chain reaction-restriction fragment length polymorphism method. After statistical analysis of the observed genotypes, a significant difference (p = 0.03) could be observed regarding the incidence of TT genotype and T allele in boys with SMA type I compared with affected girls. However, this result cannot be assessed because of the small and unequal number of subjects. We concluded that there might be no association between perlecan gene polymorphism and SMA type I disease.