Mongolism in Three Siblings with 46 Chromosomes

Publisher Website
Google Scholar
Abstract
PATIENTS with the clinical syndrome of mongolism have been shown to have 47 chromosomes instead of the 46 that are present in the normal human karyotype.1 2 3 The additional chromosome, a member of the small acrocentric group (Denver numbering system, Group 21–224), occurs as a result of failure of a pair of sister chromosomes to separate during meiosis; this process is called nondisjunction. Thus, patients with mongolism are trisomic for one of the pairs in Group 21–22. The difficulty in distinguishing pair No. 21 from 22 has recently been emphasized by Ferguson-Smith and Handmaker,5 who believe that the "mongol" chromosome . . .