Application Of MLPA In Molecular Diagnosis And Prenatal Diagnosis Of Spinal Muscular Atrophy

Objective:Spinal Muscular Atrophy (SMA) is the second most common lethal autosomal recessive neurodegenerative disease which there is no effective treatment for this disease till now. The principles of prevention the disease and reducing the rate of birth defects are based on the interruption of genetic transmission and antenatal diagnosis in SMA families. In this study, Multiple Ligation-dependent Probe Amplification (MLPA) technology is used in the screening of the SMA families. Then to investigate the application value of MLPA technology in the prenatal diagnosis of SMA which could help to reduce birth defects and improve the quality of the population.Methods:3 SMA families (10 cases) were collected from the first affiliated hospital of Guangxi Medical University’s Prenatal and Genetic Disease Diagnostics Center, peripheral blood samples and 16-24+6 weeks of gestation amniotic fluid were collected. Genomic DNA of all the SMA families members and amniotic fluid DNA were extracted by TIANGEN kit, and the expression levels of survival of motor neuron (SMN) gene was detected by MLPA.Results:Among the 3 SMA families, The proband of family I had homozygous deletion of the survival of motor neuron 1 (SMN1) gene exon 7 and 8 and hybrid repeat of survival of motor neuron 2 (SMN2) gene. All parents of these three families had heterozygous deletion of the SMN1 exon 7 and 8, and the mother of family I and the father of family III combined with hybrid repeat of SMN2 exon 7 and 8, the father of family II had heterozygous deletion of SMN2 exon 7 and 8. All of the fetus were diagnosed heterozygous deletion of SMN1 exon 7 and 8 and normal copy number of SMN2. After genetic counselling, the parents decided to continue the pregnancy.Conclusion:MLPA is an effective technology to detect gene deletion and mutation, with this technique we could analyze the DNA sequence qualitatively and semiquantitatively, this would also help to simplify the process of diagnosing SMA and make it more reliable. MLPA technology analyze the quantitative of SMN gene’s copy number by which we can improve diagnostic accuracy of SMA and provide reliable information for genetic counseling of SMA disease.