Partial trisomy 4q due to a maternal translocation: t(4;18)(q27;q21.31).

We report on a second trimester female fetus with 4q duplication (4q27-->4qter) and 18q deficiency (18q21.31-->qter) as the unbalanced product of a t(4;18)(q27;q21.31)mat. On fetopathological examination this fetus presented clinical features suggestive of the diagnosis of trisomy 18. A review is given of other reported patients with 4q duplication/18q deficiency.