Using human sequencing to guide craniofacial research

Abstract

A recent convergence of technological innovations has re-energized the ability to apply genetics to research in human craniofacial development. Next-generation exome and whole genome sequencing have dropped in price significantly making it relatively trivial to sequence and analyze patients and families with congenital craniofacial anomalies. A concurrent revolution in genome editing with the use of the CRISPR-Cas9 system enables the rapid generation of animal models, including mouse, which can precisely recapitulate human variants. Here we summarize the choices currently available to the research community. We illustrate this approach with the study of a family with a novel craniofacial syndrome with dominant inheritance pattern. The genomic analysis suggest a causal variant in AMOTL1 which we modeled in mice. We also made a novel deletion allele of Amotl1. Our results indicate that Amotl1 is not required in the mouse for survival to weaning. Mice carrying the variant identified in the human sequencing studies, however, do not survive to weaning in normal ratios. The cause of death is not understood for these mice complicating our conclusions about the pathogenicity in the index patient. Thus, we highlight some of the powerful opportunities and confounding factors confronting current craniofacial genetic research.

AMOTL1 De Novo Mutation Associated with Orofacial Clefting, Ocular Colobomas, an Atrial Septal Defect and Digital Anomalies: A Case Report and Review of the Literature

“…All four cases described a de novo heterozygous mutations, with one case of transmission from father to son [1]. This suggests a possible autosomal dominant pathogenic mutation.…”

“…Both father and son were tall with dysplastic ears. The father was found to have a missense mutation (c.469C>T) in a highly conserved sequence, which was passed to the son [1].…”