A case mongolism due to "hereditary translocation ·· is presented and discussed. The mother of the patient showed a Karyogram with 45-XX and G/D translocation. She had no stigmata. She had an abortio when she was 19 years old.
In the second pregnancy the amniotic fluid was gained by amniocentesis. The Karyogram showed G/D translocation mongolism. The Karyogram of the child's father was normal 46-XY.
The next off spring of these parents is expected to be either normal or a carrier as its mother is.