Universal fluorescent multiplex PCR and capillary electrophoresis for evaluation of gene conversion between SMN1 and SMN2 in spinal muscular atrophy.
We have developed a capillary electrophoresis (CE) method with universal fluorescent multiplex PCR to simultaneously detect the SMN1 and SMN2 genes in exons 7 and 8. Spinal muscular atrophy (SMA) is a very frequent inherited disease caused by the absence of the SMN1 gene in approximately 94% of patients. Those patients have deletion of the SMN1 gene or gene conversion between SMN1 and SMN2. However, most methods only focus on the analysis of whole gene deletion, and ignore gene conversion. Simultaneous quantification of SMN1 and SMN2 in exons 7 and 8 is a good strategy for estimating SMN1 deletion or SMN1 to SMN2 gene conversion. This study established a CE separation allowing differentiation of all copy ratios of SMN1 to SMN2 in exons 7 and 8. Among 212 detected individuals, there were 23 SMA patients, 45 carriers, and 144 normal subjects. Three individuals had different ratios of SMN1 to SMN2 in two exons, including an SMA patient having two SMN2 copies in exon 7 but one SMN1 copy in exon 8. This method could provide more information about SMN1 deletion or SMN1 to SMN2 gene conversion for SMA genotyping and diagnosis.
Wang
Chun-Chi
CC
School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.
Jong
Yuh-Jyh
YJ
Chang
Jan-Gowth
JG
Chen
Yen-Ling
YL
Wu
Shou-Mei
SM
D019075:Electrophoresis, Capillary / Q000379:methods; D005091:Exons; D005785:Gene Conversion / Q000235:genetics*; D017353:Gene Deletion; D018628:Gene Dosage; D005838:Genotype; D006801:Humans; D009134:Muscular Atrophy, Spinal / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics*; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics*
D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein