Precocious cerebral development associated with agenesis of the corpus callosum in mid-fetal life: a transient syndrome?

Four fetal brains are described in which the cerebrum showed precocious sulcus formation. The fetuses were 14, 17, 18 (15), and 19 (15–16) weeks of gestational age (age in parentheses according to developmental parameters). Associated lesions were characterized by insufficient insular formation and agenesis of the corpus callosum. Cases 1 and 3 had no familial anomalies, while a sib of case 2 had rhombencephalic malformations and a sib of case 4 lissencephaly. Case 2 showed further brain malformation including a migration disorder in the cerebrum and case 3 was associated with a Turner syndrome. The precociously formed sulci may be covered during further development of the brain so that this may well be a transient syndrome that occurs in mid-fetal life. Received: 13 June 1995 / Revised, accepted: 8 September 1995