We report a family with band heterotopia in a mother and daughter and
lissencephaly in a son (X-linked inheritance pattern). Postmortem exam
ination of the boy revealed classical lissencephaly and, among other f
indings, simplified and discontinuous inferior olives without inferior
olivary heterotopia. The absence of inferior olivary heterotopia may
distinguish X-linked lissencephaly from other conditions with classic
lissencephaly such as Miller-Dieker syndrome.