INTERACTION BETWEEN UNDULATED AND PATCH LEADS TO AN EXTREME FORM OF SPINA-BIFIDA IN DOUBLE-MUTANT MICE

The aetiology of spina bifida involves genetic and environmental facto rs, which may be why major genes contributing to pathogenesis have not been identified. Here we report that undulated-Patch double-mutant mi ce have a phenotype reminiscent of an extreme form of spina bifida occ ulta in humans. This unexpected phenotype in double-mutant but not sin gle-mutant mice shows that novel congenital anomalies such as spina bi fida can result from interaction between products of independently seg regating loci. This example of digenic inheritance may explain the oft en sporadic nature of spina bifida in humans.