Abstract
Background Some spinal muscular atrophy (SMA) cases are caused by either compound heterozygosity with a point mutation in one allele and a deletion in the other or compound heterozygous point mutations in SMN1 or other genes. Methods To explore more genes and mutations in the onset of SMA, 83 whole blood samples were collected from 28 core families of clinically suspected SMA, and multiplex ligation probe amplification (MLPA) was firstly performed with a SALSA MLPA Kit P021 for preliminary diagnosis. Afterwards, the complete gene sequence of SMN1 gene was detected with the high-throughput sequencing platform of Illumina HiSeq-2500 to find more mutations in the 28 core families. Furthermore, 20 SMA patients were selected from the 28 prodands, and 5 non SMA children as controls. The Life Technologies SOLiD™ technology with mate-pair chemistry was utilized to conduct the whole exome high-throughput sequencing. Results MLPA results showed that 22 probands were SMA patients, 3 probands carriers, and 3 probands normal individuals. Moreover, 2 parents from 2 SMA families were with 3 SMN1 exon7 copies. 6 SMN1 single nucleotide variants (SNVs) were identified in the 83 samples, and c.[84C>T], c.[271C>T], c.[-39A>G] and g.[70240639G>C] were novel. Compared with control group, 9102 mutation were selected out in SMA patients. SPTA1 mutation c.[-41_-40insCTCT], FUT5 SNV c.[1001A>G], and MCCC2 SNV c.[-117A>G] were the 3 most frequent mutations in SMA group (95%, 85% and 75%, respectively). Conclusions We identified some mutations in both SMN1 and other genes, and c.[271C>T], c.[-41_-40insCTCT], c.[1001A>G] and c.[-117A>G] might be associated with the onset of SMA.
High-Throughput Screening for Induced Point Mutations