We present the cases of two sisters, daughters of healthy, non-consanguineous parents, who have a clinical syndrome characterized by microcephaly, cortical dysplasia, ventriculomegaly, hypoplasia of the corpus callosum, hypogenesis of the cerebellar vermis, cataracts, microphthalmia, optic nerve atrophy, retinal coloboma, weight and height below 3rd centile, severe mental retardation, no speech, inability to sit, no sphincter control and a spastic tetraparesis. The facies are mildly dysmorphic, but not distinctive. No metabolic, nor chromosomal anomalies were found. The cases are very similar to, but not identical, to those described by Warburg et al [Am J Med Genet (1993) 147:1309-1312] as Micro syndrome.