Non-syndromic cleft lip with or without cleft palate (nsCL/P) is a frequent orofacial malformation. The comparison of concordance rate observed in monozygotic and dizygotic twins supports high level of heritability and a strong genetic component. However, phenotype concordance for orofacial cleft in monozygotic twins is about 50%. The aim of the present investigation was to detect postzygotic events that may account for discordance in monozygotic twins. High-density SNP microarrays hybridization was used to genotype two pairs of monozygotic twins discordant for nsCL/P. Discordant SNP genotypes and copy number variants were analyzed to identify genetic differences responsible of phenotype discrepancy. A number of differences were observed, none involving known nsCL/P candidate genes or genomic regions. Considering the limitation of the study, related to the small sample size and to the large-scale investigation method, the results suggest that the detection of discordant events in other monozygotic twin pairs would be remarkable and warrant further investigations.

中文翻译：

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胎唇裂或不裂裂双胞胎对的拷贝数变异分析。

非综合征性唇裂伴或不伴有left裂（nsCL / P）是一种常见的口面部畸形。在单卵双卵和双卵双卵中观察到的一致性率的比较支持高水平的遗传力和强大的遗传成分。然而，在单卵双胞胎中口面部裂口的表型一致性约为50％。本研究的目的是检测可能导致单卵双胎不一致的合子后事件。使用高密度SNP芯片杂交对两对与nsCL / P不符的单卵双胞胎进行基因分型。分析不一致的SNP基因型和拷贝数变异，以鉴定造成表型差异的遗传差异。观察到许多差异，没有涉及已知的nsCL / P候选基因或基因组区域。考虑到这项研究的局限性，