A patient with extreme variation in number and size of small marker chromosomes.

We describe extensive variation in the morphology and number of small marker chromosomes in a young girl whose most significant clinical findings were pulmonic stenosis, neck webbing, proptosis, camptodactyly, and developmental delay. Many of the markers had a ring structure. Some were clearly rod-shaped chromosomes with varying arm ratios and others were so small that we could not determine their structure.