Translocation 46XY, t (17;18) (q25;q21) in a mentally retarded boy with progressive eye abnormalities.

A 10-year-old boy with reciprocal translocation between chromosomes 17 and 18- 46XY,t (17;18) (q25; q21), appeared cytogenetically balanced. The patient was a healthy, thriving boy whose main abnormal feature was moderate mental retardation. However, abnormal ocular signs were present, including macular "fibrosis", optic disc abnormalities with a traction retinal detachment, tapeto-retinal degeneration, and tilting of the disc to the nasal side. These changes are consistent with the ocular changes previously described in the 18q- syndrome, suggesting that there has been a minimal deletion of chromosome material at the 18q21 breakpoint. The case also demonstrates that the ocular changes of the 18- syndrome may be progressive.