Mowat-Wilson syndrome is a recently delineated severe mental retardation, 
multiple congenital anomalies syndrome caused by dominant nonsense or frameshift 
mutations, deletions or translocations of the zinc finger homeobox 1B gene 
(ZFHX1B). We report on a patient with exceptional mild phenotype caused by a 
novel and unusual splice mutation in the 5'UTR. The aberrant transcript leads to 
usage of an alternative upstream start codon. The resulting protein differs from 
the wild-type only in the first 24 amino acids. The aberrant protein therefore 
contains all known functional domains, but might lack a so far unrecognized 
putative N-terminal acylation site, which is probably important for neuronal 
function and facial structures.