Molecular genetics of spinal muscular atrophy: contribution of the NAIP gene to clinical severity.
Spinal muscular atrophy (SMA) is one of the most common autosomal recessive disorders characterized by degeneration of anterior horn cells in the spinal cord, and leads to progressive muscular weakness and atrophy. At least three SMA-related genes have been identified: SMN1, NAIP and p44t. We analyzed these genes in 32 SMA patients and found that the SMN1 gene was deleted in 30 of 32 patients (94 %), irrespective of clinical type. The NAIP gene was deleted in 6 patients and its deletion rate was higher in type I patients than that in type U or  V. Further, in type I patients lacking the NAIP gene, deterioration in their respiratory function is more rapid than in those type I patients retaining the NAIP gene. Since complete p44t deletion was observed in only 3 patients, the correlation between the p44t deletion and severity of SMA remained ambiguous. We concluded that the NAIP deletion was closely related to the clinical severity of SMA and was a predictive marker of SMA prognosis, while the SMN1 deletion did not correlate with clinical severity.
Akutsu
Tomoko
T
Division of Pediatrics, Department of Development and Aging, Kobe University Graduate School of Medicine, Japan. akutsu@med.kobe-u.ac.jp
Nishio
Hisahide
H
Sumino
Kimiaki
K
Takeshima
Yasuhiro
Y
Tsuneishi
Syuichi
S
Wada
Hiroko
H
Takada
Satoshi
S
Matsuo
Masafumi
M
Nakamura
Hajime
H
D000328:Adult; D002648:Child; D002675:Child, Preschool; D017362:Cyclic AMP Response Element-Binding Protein; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008967:Molecular Biology / Q000379:methods; D009134:Muscular Atrophy, Spinal / Q000235:genetics* / Q000503:physiopathology; D009419:Nerve Tissue Proteins / Q000235:genetics*; D051616:Neuronal Apoptosis-Inhibitory Protein; D016601:RNA-Binding Proteins; D055532:SMN Complex Proteins; D012720:Severity of Illness Index; D055533:Survival of Motor Neuron 1 Protein
D017362:Cyclic AMP Response Element-Binding Protein; C496800:NAIP protein, human; D009419:Nerve Tissue Proteins; D051616:Neuronal Apoptosis-Inhibitory Protein; D016601:RNA-Binding Proteins; D055532:SMN Complex Proteins; C526471:SMN1 protein, human; D055533:Survival of Motor Neuron 1 Protein