A 46,XY, del(18)(pter leads to p1 100:) cebocephalic child from a 46,XX,t(12;18)(18pter leads to 18 p 1100:: 12qter leads to 12pter) normal parent.

A normal female with an 18p--chromosome but without any feature of the 18p--syndrome produced a cebocephalic child whose karyotype included an 18p--chromosome. Evidence is presented that the normal female is a nonreciprocal translocation heterozygote resulting from the short arm of one chromosome 18 becoming attached to the long arm of a chromosome 12.