Chapter 12, Problem 1CS

Roberts syndrome is a rare inherited disorder characterized by facial defects as well as severe limb shortening, extra digits, and deformities of the knees and ankles. A cytogenetic analysis of patients with Roberts syndrome, using Giemsa staining or C-banding, reveals that there is premature separation of centromeres and other heterochromatic regions during mitotic metaphase instead of anaphase. A couple with an affected infant is contacted by a local organization dedicated to promoting research on rare genetic diseases, asking if they can photograph the infant as part of a campaign to obtain funding for these conditions. The couple learned that the privacy of such medical images is not well protected, and they often are subsequently displayed on public websites. The couple was torn between helping to raise awareness and promoting research on this condition and sheltering their child from having his images used inappropriately. Several interesting questions are raised.

In Roberts syndrome, how could premature separation of centromeres during mitosis cause the wide range of phenotypic deficiencies?