The results of the genetic testing suggest the possibility of a rare variant contributing to the risk of midline craniosynostosis shared among the triplets, with potential modifiers at other genetic loci affecting the phenotype. We speculate mutations at loci within non-coding regions not captured by our genetic analysis may have been involved. Moreover, epigenetic factors as well as environmental factors including, but not limited to, in utero head constraint could have contributed to the observed phenotype.