Discovery of specific mutations in spinal muscular atrophy patients by next-generation sequencing.

Spinal muscular atrophy (SMA) is a type of autosomal recessive genetic disease, which seriously threatens the health and lives of children and adolescents. We attempted to find some genes and mutations related to the onset of SMA. Eighty-three whole-blood samples were collected from 28 core families, including 28 probands with clinically suspected SMA (20 SMA patients, 5 non-SMA children, and 3 patients with unknown etiology) and their parents. The multiplex ligation probe amplification (MLPA) was performed for preliminary diagnosis. The high-throughput sequencing technology was used to conduct the whole-exome sequencing analysis. We analyzed the mutations in adjacent genes of SMN1 gene and the unique mutations that only occurred in SMA patients. According to the MLPA results, 20 probands were regarded as experimental group and 5 non-SMA children as control group. A total of 10 mutations were identified in the adjacent genes of SMN1 gene. GUSBP1 g.[69515863G>A], GUSBP1 g.[69515870C>T], and SMA4 g.[69515738C>A] were the top three most frequent sites. SMA4 g.[69515726A>G] and OCLN c.[818G>T] have not been reported in the existing relevant researches. Seventeen point mutations in the DYNC1H1 gene were only recognized in SMA children, and the top two most common mutations were c.[2869-34A>T] and c.[345-89A>G]; c.[7473+105C>T] was the splicing mutation that might change the mRNA splicing site. The mutations of SMA4 g.[69515726A>G], OCLN c.[818G>T], DYNC1H1 c.[2869-34A>T], DYNC1H1 c.[345-89A>G], and DYNC1H1 c.[7473+105C>T] in the adjacent genes of SMN1 gene and other genes might be related to the onset of SMA.

Association of neural tube defects with maternal alterations and genetic polymorphisms in one-carbon metabolic pathway.

BACKGROUND: Neural tube defects (NTDs) are birth defects of the brain, spine, or spinal cord invoked by the insufficient intake of folic acid in the early stages of pregnancy and have a complex etiology involving both genetic and environmental factors. So the study aimed to explore the association between alterations in maternal one-carbon metabolism and NTDs in the offspring. METHODS: We conducted a case-control study to get a deeper insight into this association, as well as into the role of genetic polymorphisms. Plasma concentrations of folate, homocysteine (Hcy), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) and genotypes and alleles distributions of 52 SNPs in 8 genes were compared for 61 women with NTDs-affected offspring and 61 women with healthy ones. RESULTS: There were significant differences between groups with regard to plasma folate, SAM, SAH and SAM/SAH levels. Logistic regression results revealed a significant association between maternal plasma folate level and risk of NTDs in the offspring. For MTHFD1 rs2236225 polymorphism, mothers having GA genotype and A allele exhibited an increased risk of NTDs in the offspring (OR = 2.600, 95%CI: 1.227-5.529; OR = 1.847, 95%CI: 1.047-3.259). For MTHFR rs1801133 polymorphism, mothers having TT and CT genotypes were more likely to affect NTDs in the offspring (OR = 4.105, 95%CI: 1.271-13.258; OR = 3.333, 95%CI: 1.068-10.400). Moreover, mothers carrying T allele had a higher risk of NTDs in the offspring (OR = 1.798, 95%CI: 1.070-3.021). For MTRR rs1801394 polymorphism, the frequency of G allele was significantly higher in cases than in controls (OR = 1.763, 95%CI: 1.023-3.036). Mothers with NTDs-affected children had higher AG genotype in RFC1 rs1051226 polymorphism than controls, manifesting an increased risk for NTDs (OR = 3.923, 95%CI: 1.361-11.308). CONCLUSION: Folic acid deficiency, MTHFD1 rs2236225, MTHFR rs1801133, MTRR rs1801349 and RFC1 rs1051226 polymorphisms may be maternal risk factors of NTDs.