The 18-Trisomy Syndrome

Abstract

THREE different syndromes are reported to be caused by trisomy of the smaller autosomal chromosomes — mongolism, 18-trisomy syndrome and D1-trisomy syndrome. Everyone agrees that mongolism is caused by trisomy, whether full or partial, but it is not yet known which of the two smallest pairs of acrocentric chromosomes is involved. Four cases of D₁-trisomy syndrome have been described by the Wisconsin group,^{1 2 3} as have 6 cases of 18-trisomy syndrome.^{4 , 5} One case reported by Edwards et al.⁶ resembles the latter syndrome, but the authors considered it to be caused by trisomy of chromosome 17. Crawfurd⁷ also presented a . . .