Mutation analysis of SMN gene in a patient and his family with spinal muscular atrophy / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To perform mutation analysis and describe the genotype of the SMN gene in a patient with spinal muscular atrophy (SMA) and his family.</p><p><b>METHODS</b>Deletion analysis of the SMN1 exon 7 by conventional PCR-restriction fragment length polymorphism (RFLP) and allele-specific PCR, and gene dosage of SMN1 and SMN2 by multiplex ligation-dependent probe amplification (MLPA) were performed for the patient and his parents; reverse transcriptase (RT)-PCR and sequencing were performed for the patient. To determine whether the SMN variant was exclusive to transcripts derived from SMN1, the RT-PCR product of the patient was subcloned and multiple clones were sequenced directly; PCR of SMN exon 5 from the genomic DNA of the parents and direct sequencing were performed to confirm the mutation.</p><p><b>RESULTS</b>In SMN1 exon 7 deletion analysis, no homozygous deletion of the SMN1 was observed in the family; the gene dosage analysis by MLPA showed that the patient had 1 copy of SMN1 and 1 copy of SMN2 his father had 2 copies of SMN1 and 2 copies of SMN2, and his mother had 1 copy of SMN1 and no SMN2. A previously unreported missense mutation of S230L was identified from the patient and this mutation was also found in his father.</p><p><b>CONCLUSION</b>A novel missense mutation of S230L was identified in the SMA family and the genotype of the family members were investigated.</p>