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Chromosome 21 monosomy MeSH Supplementary Concept Data 2026
The loss (ANEUPLOIDY) of portions of of chromosome 21 result in an increased probability of congenital abnormalities, developmental delay, and intellectual disability. The severity depends on the location and size of the deleted region: proximal and distal deletions are more moderate, whereas deletion of the 21q22 region can cause craniofacial abnormalities, HEART SEPTAL DEFECTS, and severe intellectual disability.