17-18 Trisomy Syndrome

Abstract

Since the first human chromosomal abnormality was demonstrated in 1959 in a patient with Down's syndrome (mongolism),¹ numerous aberrations in the human chromosome pattern have been recognized and reported. The clinical picture of Down's syndrome is so well defined that it is not necessary routinely to employ chromosome studies to establish the diagnosis. The analysis of the karyotype, however, is extremely useful in those cases which are clinically borderline or which are of interest from the viewpoint of genetic counseling. Two other clinical syndromes have been associated with the presence of an extra autosomal chromosome. One is the 13-15 or D trisomy which was described in 1960 by Patau et al ² and recently reviewed by Smith et al ³; the other is that involving trisomy in group 17-18 or group E.^2,4 Since only a small number of cases having a trisomy in either of these groups has