Exploration of genetic factors determining cleft side in a pair of monozygotic twins with mirror-image cleft lip and palate using whole-genome sequencing and comparison of craniofacial morphology

Publication date: Available online 19 August 2018

Source: Archives of Oral Biology

Author(s): Masahiro Takahashi, Kazuyoshi Hosomichi, Tetsutaro Yamaguchi, Ryo Nagahama, Hiroshi Yoshida, Mary L. Marazita, Seth M. Weinberg, Koutaro Maki, Atsushi Tajima

Abstract

Objective

The aim of the present study is to explore genetic factors determining difference of cleft side using whole-genome sequencing and evaluation of craniofacial morphology using cephalometric analysis between Japanese monozygotic (MZ) twins with mirror-image cleft lip and palate (CLP).

Design

We selected a Japanese MZ twin pair (MZ-A and MZ-B) affected with unilateral CLP who are discordant for cleft side (left/right) and conducted whole-genome sequencing to identify genetic factors determining cleft side. Moreover, we compared their craniofacial morphologies using cephalograms.

Results

Whole-genome sequencing results suggested that no discordant DNA variants were found between MZ-A and MZ-B. The comparison of craniofacial morphology between the MZ twins revealed that MZ-B had maxillary deficiency and slightly more mandibular protrusion than MZ-A.

Conclusions

It is indicated that environmental factors might be a critical factor that influences the determination of difference of cleft side in orofacial clefts. In addition, we found some differences in craniofacial morphology between MZ-A and MZ-B. Our findings suggest that various environmental factors, such as epigenetics, might be a critical factor that influences the determination of difference of cleft side in CLP rather than inherited genetic factors.

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