We report two siblings from non consanguineous parents with a similar MCA/MR syndrome: Pre- and postnatal growth retardation, microcephaly, mental retardation, iris colobomata, facial dysmorphism, spasticity, dilated ventricles and abnormal immunoglobulin levels. Review of published reports and the use of the London Dysmorphology Database suggests that these siblings may present a new syndrome.