In silico identification of new candidate genes for hereditary congenital facial paresis

Hereditary congenital facial paresis (HCFP) consists of the paralysis or weakness of facial muscles caused by a maldevelopment of the facial branchiomotor (FBM) nucleus and its nerve. Linkage analyses have related this disorder to two loci, HCFP1 and HCFP2, placed respectively in human chromosomes 3q21.2-q22.1 and 10q21.3-q22.1, but the causative genes are still unknown. In this work we aimed to identify which genes from these loci are expressed in the developing hindbrain and particularly in the FBM nucleus. To this end, we retrieved from the ENSEMBL genomic database the list of these genes as well as their respective mouse orthologs. Subsequently we examined their respective expression patterns in the mouse embryo by using the GenePaint gene expression database. As a result of this screening, we found a new gene (Mgll) from the HCFP1 locus that has strong and specific expression in the developing FBM nucleus. In its turn, the HCFP2 locus appeared as a large gene-desert region, flanked by two genes, Reep3, with specific expression in the FBM nucleus, and Lrrtm3, broadly expressed in the brainstem, including the same nucleus. The concurrence of genomic position and neural expression pattern makes these genes new potential candidates for HCFP.

Research highlights
► HCFP disease involves maldevelopment of the facial branchiomotor nucleus.
► We analysed the expression pattern of genes from 2 genetic loci linked to HCFP.
► Mgll from the HCFP1 locus is expressed in the facial branchiomotor nucleus.
► Reep3 and Lrrtm3, flanking the HCFP2 locus, are also expressed in that nucleus.
► Mgll, Reep3 and Lrrtm3 are new putative candidate genes for HCFP.