Non-syndromic cleft palate: analysis of TBX22 exon 5 gene mutation

Position-dependent correlation between TBX22 exon 5 methylation and palatal shelf fusion in the development of cleft palate

DNA methylation is essential for spatiotemporally-regulated gene expression in embryonic development. TBX22 (Chr X: 107667964-107688978) functioning as a transcriptional repressor affects DNA binding, sumoylation, and transcriptional repression associated with X-linked cleft palate. This study aimed to explore the relationship and potential mechanism between TBX22 exon 5 methylation and palatal shelf fusion induced by all-trans retinoic acid (ATRA). We performed DNA methylation profiling, using MethylRAD-seq, after high throughput sequencing of mouse embryos from control (n=9) and ATRA-treated (to induce cleft palate, n=9) C57BL/6J mice at embryonic gestation days(E) 13.5, 14.5 and 16.5. TBX22 exon 5 was hyper-methylated at the CpG site at E13.5 (P=0.025, log2FC=1.5) and E14.5 (P=0.011, log2FC:1.5) in ATRA-treated, whereas methylation TBX22 exon 5 at the CpG site was not significantly different at E16.5 (P=0.808, log2FC=-0.2) between control and ATRA-treated. MSP results showed a similar trend consistent with the MethylRAD-seq results. qPCR showed the change in TBX22 exon 5 expression level negatively correlated with its TBX22 exon 5 methylation level. These results indicate that changes in TBX22 exon 5 methylation might play an important regulatory role during palatal shelf fusion, and may enlighten the development of novel epigenetic biomarkers in the treatment of CP in the future.

Lingual frenotomy in neonates: past, present, and future

During the last decade, increasing awareness of breastfeeding and its health benefits has not been reflected in the provision of lingual frenotomy in neonates with tongue-tie. This could be because of inconsistencies in our understanding of the importance and treatment of ankyloglossia. In this review, we discuss the current clinical guidance on diagnosis and management, and the future of such a service in the early postpartum period.