Eif2b3 mutants recapitulate phenotypes of vanishing white matter disease and validate novel disease alleles in zebrafish

Leukodystrophy with vanishing white matter (VWM), also called Childhood Ataxia with Central Nervous System Hypomyelination, is caused by mutations in the subunits of the eukaryotic translation initiation factor, EIF2B1, EIF2B2, EIF2B3, EIF2B4 or EIF2B5. However, little is known regarding the underlying pathogenetic mechanisms, and there is no curative treatment for VWM. In this study, we established the first EIF2B3 animal model for VWM disease in vertebrates by CRISPR mutagenesis of the highly conserved zebrafish ortholog eif2b3. Using CRISPR, we generated two mutant alleles in zebrafish eif2b3, 10- and 16-bp deletions, respectively. The eif2b3 mutants showed defects in myelin development and glial cell differentiation, and increased expression of genes in the induced stress response pathway. Interestingly, we also found ectopic angiogenesis and increased VEGF expression. Ectopic angiogenesis in the eif2b3 mutants was reduced by the administration of VEGF receptor inhibitor SU5416. Using the eif2b3 mutant zebrafish model together with in silico protein modeling analysis, we demonstrated the pathogenicity of 18 reported mutations in EIF2B3, as well as of a novel variant identified in a 19-month-old female patient: c.503 T > C (p.Leu168Pro). In summary, our zebrafish mutant model of eif2b3 provides novel insights into VWM pathogenesis and offers rapid functional analysis of human EIF2B3 gene variants.

Investigation of candidate genes of non-syndromic cleft lip with or without cleft palate, using both case-control and family-based association studies

OBJECTIVE

Non-syndromic cleft of the lip and/or palate (NSCL/P) is one of the most common polygenic diseases. In this study, both case-control and family-based association study were used to confirm whether the Single Nucleotide Polymorphisms (SNPs) were associated with NSCL/P.

METHODS

A total of 37 nuclear families and 189 controls were recruited, whose blood DNA was extracted and subjected to genotyping of SNPs of 27 candidate genes by polymerase chain reaction-improved multiple ligase detection reaction technology (PCR-iMLDR). Case-control statistical analysis was performed using the SPSS 19.0. Haplotype Relative Risk (HRR), transmission disequilibrium test (TDT), and Family-Based Association Test (FBAT) were used to test for over-transmission of the target alleles in case-parent trios. The gene-gene interactions on NSCL/P were analyzed by Unphased-3.1.4.

RESULTS

In case-control statistical analysis, only C14orf49 chr14_95932477 had statistically significant on genotype model (P = .03) and allele model (P = .03). Seven SNPs had statistically significant on TDT. None of 26 alleles has association with NSCL/P on FBAT. Some SNPs had haplotype-haplotype interactions and genotype-genotype interactions.

CONCLUSION

C14orf49 chr14_95932477 was significantly different between cases and controls on genotype model and allele model by case-control design. Seven SNPs were significantly different on HRR. Four SNPs were significantly different on TDT.