Application of multiplex competitive PCR combined with capillary electrophoresis in carrier screening of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is an autosomal recessive, fatal neurological disorder in children. The pathogenic gene of SMA is survival motor neuron1 (SMN1). There are many methods to detect SMN1 gene copy number, but few techniques are suitable for large-scale population screening. In order to find a rapid and accurate experimental technique for mass screening of SMA carriers in the population, the SMN1 gene copy number of 12 SMA patients and their parents was analyzed by multiplex competitive PCR combined with capillary electrophoresis. Meanwhile, the copy number of SMN1 gene in 151 healthy pregnant women in Jiangsu was screened with the MLPA technology to confirm their copy number of the SMN genes. The results showed that the 12 SMA patients had 0 copy of SMN1 gene, and all their parents had 1 copy of SMN1 gene only. Among 151 healthy subjects, 3 cases (2.0%) had 1 copy of SMN1 gene, and hence designated as SMA carriers. One hundred and thirty-four cases (88.7%) had 2 copies of the SMN1 gene. There were 14 cases (9.3%) with more than 2 copies of the SMN1 gene. Therefore, multiplex competitive PCR combined with capillary electrophoresis is a rapid, simple and accurate method for the detection of SMA carriers; and potentially applicable to mass screening of SMA carriers in the population.