A re-investigation of an inherited chromosome aberration in a girl with signs of De Lange syndrome.

An earlier report in this journal (1968) dealt with an inherited chromosome aberration in a girl with signs of de Lange syndrome and her family. A translocation between a 13--15 and a 4--5 chromosome, with the unbalanced proposita having an additional segment from one end of a 13--15 chromosome was found. A 6--12 chromosome involvement could not be excluded. The mother and two phenotypically normal sisters had a balanced karyotype. With modern technique a more complex translocation has been found. A part of one chromosome no. 5 is translocated to one chromosome no. 9, a fragment of this chromosome is probably translocated to one chromosome no. 13, and a part of this one is translocated to the first-mentioned chromosome no. 5. The mother and sisters have this balanced chromosomal aberration. The proposita in addition has two normal chromosomes no. 13. Thus she has a partial trisomy of chromosome no. 13. Reinvestigation of older reports on chromosomal aberrations in risk families in order to achieve a more reliable diagnosis in phenotypically normal members of the same family is emphasized.