UNBALANCED TRANSLOCATION IN A MOTHER AND HER SON IN ONE OF 2 5-10 TRANSLOCATION FAMILIES

We present two families with different distal long arm 5;10 translocat ions. In one family the propositus and his mother inherited the same d erived chromosome 10 from the maternal grandfather who has a balanced t(5;10)(q35.3;q26.13), The phenotype of both the affected patients is milder and only partially overlaps with that of previous cases of dist al 10q deletion, Other previously reported cases of transmitted imbala nce are also remarkable for mild phenotype, occurrence of deletions ra ther than duplications and a strong bias toward maternal as opposed to paternal transmission. In the second family, the propositus inherited a derived chromosome 10 from his mother who carries a balanced t(5;10 )(q35.1; q26.3) translocation; his clinical manifestations are consist ent with an emerging phenotype for distal 5q duplications. (C) 1996 Wi ley-Liss, Inc.