Defective growth in the anterior palate of Msx1-/- and Fgf10-/- mice leads to a complete cleft palate and supports the anterior-to-posterior direction of palatal closure.
Since the Msx1 mouse knockout has cleft palate and MSX1 mutations have been found in rare cases of syndromic CL/P, this locus is especially plausible for linkage.
No significant association was found between NSOC and rs3821949 or rs12532 in MSX1 gene, whereas an association was observed between the P147Q variant and cleft lip with cleft palate in the case-control analysis.
We pointed to: (i) a role of FOXE1 in controlling the expression of MSX1 and TGF-β3 relevant in craniofacial development and (ii) a causative part of FOXE1 mutations or mice Foxe1(-/-) genotype in the pathogenesis of cleft palate in the Bamforth-Lazarus syndrome.
Prior studies have implicated an involvement of the Msx1 homeobox gene in cleft palate in mice and its homolog in humans (called MSX1 in the HOX7 gene, located on chromosome 4).
Transgenic expression of human Bmp4 driven by the mouse Msx1 promoter in the Msx1(-/-) palatal mesenchyme rescued the cleft palate phenotype and neonatal lethality.
By comparison, risk estimates for maternal alcohol consumption (> or = 4 drinks/month) were significantly elevated for CLP and were most elevated among infants with allelic variants at the MSX1 site.
The Msx1-/Msx1- phenotype is similar to human cleft palate, and provides a genetic model for cleft palate and oligodontia in which the defective gene is known.
These results are consistent with evidence from other studies in the US and Chile and confirm the importance of the MSX1 genotype in determining the risk of CL/P and CP in Koreans.