Partial trisomy 4q: two cases with a familial translocation t(4;18)(q27;q23).

Clinical and cytogenetic data of two related patients, both trisomic for the segment 4q27 to qter, are reported. Familial studies determined that the mothers of the two probands were carriers of the same balanced translocation between chromosomes 4 and 18. Altogether, two partial trisomies 4q, five balanced karyotypes, and one 45,X0 karyotype were found in the family. The 18 cases reported to date are reviewed with respect to the karyotype-phenotype correlation.