Altered binding of MYF-5 to FOXE1 promoter in cleft palate.

Objectives: Three different homozygous loss-of-function mutations of the Forkhead box E1 (FOXE1) gene have been associated with syndromic cleft palate. Here we screened the entire promoter region to identify variations in significant consensus motifs affecting the transcription. Methods: Genomic DNA of 40 healthy people and genomic and somatic DNA from 32 patients affected by cleft palate (CP) without or with CHARGE syndrome and 1 patient affected by Bamforth-Lazarus syndrome were analyzed by automatic sequencing. To identify transcription factor binding sites the Transcription Element Search System (TESS) program was employed. Results: Known polymorphisms in the promoter and coding regions were detected with frequencies similar to those reported in literature. In 11 CP patients a novel non-coding polymorphism in the 5-untranslated region of FOXE1 was found in both genomic and somatic DNAs. The variation fell into a putative consensus sequence for the transcription factor MYF-5 and completely impaired the ability of MYF-5 to bind to its motif. Conclusions: In 35% of CP patients a novel homozygous polymorfism that prevents the binding of MYF-5 to FOXE1 promoter has been found. This polymorphic variation highlights for the first time the role of FOXE1 expression in the pathogenesis of cleft palate. Since recent data highlight the role of MYF-5 in the craniofacial skeletal development depending on functional muscles and in the fusion of primary palate and secondary palate with each other, results reported here strongly suggest a more significant involvement of this factor in the cleft palate onset.