Deletion analysis in Turkish patients with spinal muscular atrophy.

Childhood proximal spinal muscular atrophy (SMA) is an autosomal recessive disorder which presents as a severe, intermediate or mild condition. Here we present the molecular analysis of SMA candidate genes, the survival motor neuron gene (SMN), the neuronal apoptosis inhibitory protein gene (NAIP) and the p44 gene. Deletion frequency rate of these candidate genes is 93% in 106 Turkish SMA patients. Various deletion haplotypes by using genotypes of SMN, NAIP and p44 genes are constructed. Haplotype A, which is the deletion of all three involved genes, was found only in the most severe group with an early onset of usually less than 2 months of age.