ANALYSIS OF CHROMOSOME 5Q13 GENES IN AMYOTROPHIC-LATERAL-SCLEROSIS - HOMOZYGOUS NAIP DELETION IN A SPORADIC CASE

Although defects in the gene encoding she enzyme cytosolic copper/zinc superoxide dismutase (SOD1) have been reported in 20% of familial amy otrophic lateral sclerosis (ALS) patients, the etiology of the remaini ng familial cases and the more common sporadic form of the disease rem ains unknown, Recently, deletions of the neuronal apoptosis inhibitory protein gene NAIP, of the survival motor neuron gene SMN, and of a fu rther cDNA fragment, XS2G3, have been reported in childhood-onset prox imal spinal muscular atrophy (SMA), another disorder with pathology re stricted to the motor system. We have therefore investigated the possi bility of alterations in SMN and NAIP in 154 patients with ALS (135 sp oradic cases, 17 familial cases), None of these patients revealed muta tions in SMN by single-strand conformation polymorphism analysis, A si ngle patient revealed a partial deletion of NAIP, with a homozygous ab sence of NAIP, exon 5. While it is possible that this individual is on e of the rare carriers of SMA who show NAIP deletions, a further expla nation is that the NAIP deletion is in some a;ay contributing to the A LS phenotype in this individual.