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July 21, 1969

Short Forearms and A Unique D Chromosome

Author Affiliations

Birth Defects Institute NY State Health Department, Albany

JAMA. 1969;209(3):418. doi:10.1001/jama.1969.03160160054022

To the Editor:—  The karyotype of a 21-year-old female college student with short forearms and a maternal history of two generations (Dr. Mario Montes, personal communication) revealed a chromosome abnormality not heretofore described: A D-like chromosome with satellited prominent short arms was seen in 33 of 35 metaphases (Figure).The variable density of the acetoorcein stain resembled that expected from superimposition of a small acrocentric chromosome with satellites or of satellited isochromosome fragments on the heterochromatic short arms of a D chromosome, following an incomplete break at the centromere. The unmatched chromosome was unlabeled after three hours' exposure to tritiated thymidine, as is the asynchronous early-labeling D3 (15) homologue.1Family studies were not possible; it is uncertain, then, whether the unmatched chromosome is fortuitous or is associated with the history of familial short arms.