Simple and convenient method and process for detecting SMA by DNA sequencing

Abstract

The invention relates to a simple and convenient method and specific process for detecting SMA. The key point of the technical scheme is that DNA sequencing is carried out on SMN intron 6-exon 8 in the PCR products; if exons 7 and 8 of SMN1 are homozygous deletions, only homozygous peaks of +6T on exon 7 of SMN2 and +245A on exon 8 of SMN2 are found; the method can be used for screening the molecular background of the copy number of the same SMN2 and the phenotypic deviation of the SMA; the +6 position on the exon 7 and +245 position on exon 8 of SMN appear nesting peak; if the phenotype is normal, the subject is normal people; if the subject is a patient, the point mutation of SMN1 can be preliminarily screened. The main application is as follows: the gene level of 98.6 percent of patients can be determined; the molecular background of the same SMN2 copy number and SMA phenotypic deviation can be screened; the remaining few SMA patients with loss of heterozygosity and point mutation are able to screen for point mutations in SMN1. The method is very suitable for basic medical units and is beneficial to further research on the mechanism of the disease.

Description

technical field [0001] Medical Genetics Background technique [0002] Spinal muscular atrophy (SMA) is the most common autosomal recessive neuromuscular disease. The SMN1 gene is the SMA-determining gene, which can cause disease through its gene deletion and small mutations in the gene. There are two highly homologous genes in the SMN gene. copy, telomere copy (SMN1) and centromere copy (SMN2), SMN2 is a modifying gene, currently it is believed that exon 7 and / or exon 8 deletion mutation of SMN1 gene is the main cause of SMA, about 95% of patients with SMA types I-III have homozygous SMN1 exon 7 and / or exon 8 deletions. There are only 5 nucleotide differences between SMN1 and SMN2 genes, which are intron 6 (-45G→A), exon 7 (+6C→T), intron 7 (+100A→G, + 214A→G), exon 8 (+245G→A), in SMA individuals, polymerase chain reaction-restriction fragment length polymorphism (polymerase chain reaction restriction fragment length polymorphism, PCR-RFLP) was used in the past at home an...

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The detection process is cumbersome, and it is

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