Disorder of fetal brain growth; individuals have small brains and almost always have mental retardation, although rare individuals with mild microcephaly (-3 SD) and normal intelligence have been reported. Clinical features include the features of ‘microcephaly 6, primary, autosomal recessive’ and 'Seckel syndrome', and may include short stature or mild seizures. The disease is Monarch Disease Ontology entry MONDO_0700054 (microcephaly 6 with or without short stature).