A consistent phenotype has been associated with deletion of the distal long arm of chromosome 4. An invariant requirement for the phenotype in cases described so far has been the deletion of material from within band 4q31 but few other cases have been described that further aid the delineation of the minimum critical region sufficient for the expression of the phenotype. We report a child with a small interstitial deletion within band 4q31 who exhibits most of the features of the established 4q-phenotype.