[Exploring the association between SPRY gene family and non-syndromic oral clefts among Chinese populations using data of a next-generation sequencing study].

objectiveTo explore the association between SPRY gene family and the risk of non-syndromic oral clefts among Chinese populations, in respect of single nucleotide polymorphisms (SNPs) association and parent-of-origin effects.

methodsBased on case-parent design, this study used the data of SPRY gene family in a next generation sequencing study of 183 non-syndromic cleft lip with or without cleft palate (NSCL/P) case-parent trios (549 participants) recruited from 2016 to 2018, to analyze the effects of SNP association and parent-of-origin. The sequencing study adopted a two-stage design. In the first stage, whole exome sequencing was conducted among 24 NSCL/P trios with family history to explore potential signals. Then in the second stage, another 159 NSCL/P trios were used as validation samples to verify the signals found in the first stage. The data of general information, disease features and parental environmental exposures for participants were collected through questionnaires. Blood samples were collected from each participant for DNA extraction and sequencing. Transmission disequilibrium tests (TDT) were conducted to test for the association between SNPs and NSCL/P, while Z score tests were applied to analyze parent-of-origin effects. The analyses were performed using Plink (v1.07). TRIO package in R (v3.5.1). Besides, famSKAT analyses were conducted in the first stage to combine the effect of SNPs located on the same gene, using famSKAT package in R(V3.5.1). Bonferroni method was adopted to correct multiple tests in the second stage.

resultsTwenty-two SNPs in SPRY gene family were included for analyses after the quality control process in the first stage. Based on the variants annotation, functional prediction and statistical analysis, rs1298215244 (SPRY1) and rs504122 (SPRY2) were included in the second verification stage. TDTs in the verification stage revealed that rs1298215244: T>C, rs504122: G>C and rs504122: G>T were associated with the risk of NSCL/P after Bonferroni corrections, where rs504122: G>T was a rare variation. Although the test for parent-of-origin effect of rs1298215244: T>C reached nominal significance level, no SNP showed significant association with NSCL/P through parent-of-origin effect after Bonferroni corrections.

conclusionThis study found that SNPs (including both common and rare variants) among the SPRY gene family were associated with the risk of NSCL/P among Chinese populations. This study failed to detect parent-of-origin effects among the SPRY gene family.