Sec24b Fzd3/6 And 11 Genes And Neural Tube Defects Wnt5 / Correlation Studies

Neural tube defects(NTDs) present a series of sever birth defects caused by partial or complete failure of neural tube closure during embryogenesis, including anencephaly, craniorachischisis, encephalocele, iniencephaly and spinal bifida et.al. NTDs are among the most common birth malformations, which bring huge financial and emotional burden to affected family and our society..Model organisms research indicated the planar cell polarity (PCP) pathway play an important role in neural tube closure. The so-called PCP pathway core genes inlcuded:Wnt5/11, Frizzled3/6, Vangl1/2, Dvl1/2/3, Pk1/2 etc. Sec24b, a cargo-sorting member of the core complex of the endoplasmic reticulum (ER)-to-Golgi transport vesicle COPII, is recently identified critical for neural tube closure through selectively sorting of Vangl2 into COPII vesicles. Here we reported four disease-specific SEC24B missense mutations(ie.F227S, F682L, R1248Q, A1251G) in NTDs patients. Subcellular localization showed F227S and R1248Q prevented transportation of VANGL2 from ER to Golgi, VANGL2 was trapped in the ER and unable to be located properly in plasma membrane. In addition, VANGL2 F437S mutation also affected normal subcellular localization of VANGL2. In vivo study also suggested that F227S and R1248Q were loss of function mutations compared with wildtype SEC24B.We also found SEC24B coding region SNP rs6827006 was significantly associated with NTDs.In codominant model, the fetal with A/G and G/G genotype had 1.50-fold (OR=1.50,95%CI=1.02-2.20) and 9.58-fold (OR=9.58, 95%CI=1.06-86.27) increase of NTDs risk respectively, comparing with healthy controls(P value=0.0094).Furthermore, we identified four disease-specific missense mutations of FZD6 gene (M39V,I115S,K512N,D634N) in patients with NTDs, which are highly-conserved among species and may affected the interaction between FZD6 and other core PCP gene, such as WNT or DVL. We also detected four novel low frequency SNP in 3’UTR region of WNT11 gene(3’UTR+21G>A,3’UTR+126C>T,3’UTR+(167-169)delAAQ3’UTR+265G>A), which may regulate WNT11 expression via MicroRNA binding. Luciferase assay indicated that three SNP,3’UTR+126C>T,3’UTR+(167-169)delAAG and 3’UTR+265G>A, significantly up-regulated the reporter gene expression level, respectively(p value<0.05).In conclusion, we identified and carried out function analysis of disease-specific rare mutations or low frequency SNP in PCP pathway genes SEC24B, FZD6 and WNT11,which may improve the understanding of NTDs genetic basis.