Normal/2l-Trisomy Mosaicism: Report of Four Cases and Review of the Subject

A SIGNIFICANT number of patients with Down's syndrome (mongolism) have had karyotype interpretations other than the usual 21-trisomic variety, and those with mosaic patterns were recently reviewed by Chaudhuri and Chaudhri.¹ The previously reported mosaic patients with Down's syndrome have varied greatly in their number of mongoloid features and also in results of their psychological evaluation. The intelligence quotients (IQ) in mongoloid patients with normal/21-trisomy mosaic patterns have varied from very low² to that of a normal range.³ Karyotype analyses of some mothers of 21-trisomy mongoloid children have shown normal/21-trisomy patterns, and these mothers have had few, if any, stigmata of Down's syndrome.4-7 Below is a report of findings in four outpatients who presented with physical features suggestive of Down's syndrome (mongolism) and who were found to have the normal/21-trisomy mosaic karyotype. These four patients, who were discovered during the cytogenetic study of 82 patients with mongoloid