Ring chromosome 15 and 15qs+ mosaic: clinical and cytogenetic behaviour spanning 29 years.

A phenotypic female with mild mental retardation, minor facial anomalies, and short stature has been evaluated clinically and cytogenetically over 29 years. At age 59, she remains physically well and shows no signs of dementia. Cytogenetic analysis, performed on peripheral blood specimens on 10 occasions between 1961 and 1990, showed mosaicism with one cell line containing a large stable ring (15) chromosome and another cell line without the ring but with a 15qs+. The different cell lines remained constant. The case provides information on the natural history of the ring chromosome 15 syndrome.