Birth defects | Washington State Magazine | Washington State University

Why do good eggs go bad?

In 2004, researchers at Mount Sinai School of Medicine in New York produced a line of mice with an intriguing mutation. The mice make a defective form of a protein called SMC1beta that binds to chromosomes during the crossing-over stage. Pat Hunt and Terry Hassold, on the lookout for anything that might be involved in damage to chromosomes in the eggs of older women, recognized a hot prospect.

SMC1beta is part of a complex, or cluster, of four proteins called cohesins. The complex holds the two strands of each chromosome together while they break and recombine with the strands of their partner chromosome. Hunt and … » More …

Fall 2008

To Err is Human

The older a woman is when she conceives, the more likely it is her eggs will have abnormal chromosomes. But beyond the fact of the biological clock, we often overlook a bigger story. Even with young mothers, chromosome abnormalities are the single most frequent cause of miscarriage and birth defects. Between 25 and 30 percent of all fertilized human eggs have the wrong number of chromosomes, a rate that seems peculiar to humans. » More ...