Chapter

Gonadal Cytogenetic Damage from Exposure to Extrinsic Agents

R. J. McKinlay Gardner, Grant R. Sutherland and Lisa G. Shaffer

in Chromosome Abnormalities and Genetic Counseling

Fourth edition

Published on behalf of Oxford University Press

Published in print November 2011 | ISBN: 9780195375336
Published online October 2012 | e-ISBN: 9780199975174 | DOI: http://dx.doi.org/10.1093/med/9780195375336.003.0028

Series: Oxford Monographs on Medical Genetics

Gonadal Cytogenetic Damage from Exposure to Extrinsic Agents

Show Summary Details

Preview

IN THIS CHAPTER we review what is known about the effects of some anticancer treatments, and of certain other therapeutic and environmental agents, that could conceivably have an injurious effect upon chromosomal distribution at gametogenesis, or which might cause chromosomal breakage or rearrangement in the cells of the gonad. In other words, the focus is on factors that might disturb the course of meiosis, or that might have clastogenic effects upon the chromosomes of gametocytes. We do not consider other categories of genetic damage.

Given the inherent vulnerability of gametogenesis, a logical starting position might have been that any potential damaging agent should be presumed guilty until proven innocent. As discussed in Chapter 23, large fractions of sperm and eggs, in the vicinities of 10%–20%, are chromosomally abnormal, due to aneuploidies or structural change acquired, for the most part, during meiosis. If this is what happens naturally, if gametogenesis is so susceptible normally, then surely would not agents known to compromise the integrity of the DNA and of the spindle apparatus (not to mention various artificial dietary and environmental exposures) compound the effect dramatically? Perhaps surprisingly, this seems not to be the case. Gametogenesis—provided the damage is not irreversible—often proceeds normally, or at any rate recovers, even in the setting of some heavy exposures, and no discernible increase in chromosomal abnormality is recorded in the subsequently born children. Nevertheless, if only on the pure grounds of what seems biologically reasonable and plausible, the question is not to be regarded as being closed. The fact that sperm chromosomes may, with certain agents, show an increased rate of cytogenetic abnormality is a more practical reason for maintaining a cautious view.

We outline the observations and conclusions relating to a number of medical conditions, cancer and otherwise, and touch on some environmental and lifestyle factors. The listing is not exhaustive.

Chapter.  5946 words. 

Subjects: Clinical Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Buy this work at Oxford University Press »

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.