Cvjetkovic Nevena, Maili Lorena, Weymouth Katelyn S, Hashmi S Shahrukh, Mulliken John B, Topczewski Jacek, Letra Ariadne, Yuan Qiuping, Blanton Susan H, Swindell Eric C, Hecht Jacqueline T
Department of Pediatrics, University of Texas Medical School at Houston Houston, Texas ; Graduate School of Biomedical Sciences, University of Texas Health Science Center Houston, Texas.
Department of Pediatrics, University of Texas Medical School at Houston Houston, Texas.
Mol Genet Genomic Med. 2015 Sep;3(5):440-51. doi: 10.1002/mgg3.155. Epub 2015 May 7.
Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common birth defect affecting 135,000 newborns worldwide each year. While a multifactorial etiology has been suggested as the cause, despite decades of research, the genetic underpinnings of NSCLP remain largely unexplained. In our previous genome-wide linkage study of a large NSCLP African-American family, we identified a candidate locus at 8q21.3-24.12 (LOD = 2.98). This region contained four genes, Frizzled-6 (FZD6), Matrilin-2 (MATN2), Odd-skipped related 2 (OSR2) and Solute Carrier Family 25, Member 32 (SLC25A32). FZD6 was located under the maximum linkage peak. In this study, we sequenced the coding and noncoding regions of these genes in two affected family members, and identified a rare variant in intron 1 of FZD6 (rs138557689; c.-153 + 432A>C). The variant C allele segregated with NSCLP in this family, through affected and unaffected individuals, and was found in one other NSCLP African-American family. Functional assays showed that this allele creates an allele-specific protein-binding site and decreases promoter activity. We also observed that loss and gain of fzd6 in zebrafish contributes to craniofacial anomalies. FZD6 regulates the WNT signaling pathway, which is involved in craniofacial development, including midfacial formation and upper labial fusion. We hypothesize, therefore, that alteration in FZD6 expression contributes to NSCLP in this family by perturbing the WNT signaling pathway.
非综合征性唇裂伴或不伴腭裂（NSCLP）是一种常见的出生缺陷，每年全球有13.5万名新生儿受其影响。尽管多因素病因被认为是其成因，然而经过数十年研究，NSCLP的遗传基础在很大程度上仍未得到解释。在我们之前对一个大型NSCLP非裔美国家庭进行的全基因组连锁研究中，我们在8q21.3 - 24.12处鉴定出一个候选基因座（LOD = 2.98）。该区域包含四个基因，卷曲蛋白-6（FZD6）、Ⅱ型基质蛋白（MATN2）、odd-skipped相关蛋白2（OSR2）和溶质载体家族25成员32（SLC25A32）。FZD6位于最大连锁峰下方。在本研究中，我们对两名患病家庭成员的这些基因的编码区和非编码区进行了测序，并在FZD6的内含子1中鉴定出一种罕见变异（rs138557689；c.-153 + 432A>C）。该变异的C等位基因在这个家族中与NSCLP共分离，通过患病和未患病个体传递，并且在另一个NSCLP非裔美国家庭中也被发现。功能分析表明，该等位基因创建了一个等位基因特异性蛋白结合位点并降低了启动子活性。我们还观察到斑马鱼中fzd6的缺失和增加会导致颅面异常。FZD6调节WNT信号通路，该通路参与颅面发育，包括面中部形成和上唇融合。因此，我们推测，FZD6表达的改变通过扰乱WNT信号通路导致了这个家族中的NSCLP。
