[The study of the correlation between the clinical phenotype of spinal muscular atrophy and SMN2 gene copy number].
OBJECTIVE
To detect the correlation between the clinical phenotype of spinal muscular atrophy (SMA) and survival motor neuron gene (SMN2) copy number.


METHODS
The SMN2 gene copy numbers of 57 different types of SMA were detected by real-time fluorescence quantitative PCR method with TaqMan technique.


RESULTS
Average SMN2 copy number was 1.017 +/- 0.090, 2.019+/- 0.080, 3.104+/- 0.170 in predicting one, two, three copy numbers, respectively, and CV was 8.9%, 3.9%, 5.4%, respectively. Average SMN2 copy number was 1.926+/- 0.460, 2.508+/- 0.460, 2.876+/- 0.270, in type I, II and III SMA, respectively. The SMN2 gene copy number in type II and III SMA were higher than that of type I SMA (P < 0.01). The SMN2 gene copy number in type III SMA was higher than that of type II SMA (P < 0.01). 85.72% of type I SMA patients usually had 2 SMN2 copies; 40% and 60% of type II SMA patients had 2 and 3 SMN2 copies, respectively; 82% of type III SMA patients had 3 SMN2 copies.


CONCLUSIONS
There is significant correlation between the change of SMA clinical phenotype and SMN2 cope number. The distributions of the SMN2 gene copy number are various in different types of SMA patients. All types of SMA patients have at least one copy SMN2. The SMN2 gene copy numbers in type II, III SMA are higher than that of type I. All of these findings suggest that the severity of SMA patients depend on the change of the SMN2 copy numbers.
Lu
Li-ping
LP
Laboratory Medicine, Shengjing Hospital, China Medical University, Shenyang, Liaoning, 110004 PR China.
Ma
Hong-wei
HW
Jiang
Jun
J
Wang
Tao
T
Hu
Bin
B
D018628:Gene Dosage; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D009134:Muscular Atrophy, Spinal / Q000235:genetics* / Q000473:pathology; D010641:Phenotype; D016133:Polymerase Chain Reaction; D055532:SMN Complex Proteins / Q000235:genetics*; D055540:Survival of Motor Neuron 2 Protein
D055532:SMN Complex Proteins; C526477:SMN2 protein, human; D055540:Survival of Motor Neuron 2 Protein