Recently, staff at the Zhangzhou Institute of Medical Science in east China?s Fujian Province examined the chromosomes of a woman who has lost four babies due to spontaneous abortions in the second month of pregnancy. The staff detected abnormalities in her chromosomes. Identified by Xia Jiahui, a member of the National Key Laboratory of Medical Genetics of China, and other experts as abnormalities in the chromosomal nucleus, the results were revealed to the world for the first time. The institute has discovered and disclosed five different kinds of chromosomal abnormalities.
Humans have 23 pairs of chromosomes. Abnormal chromosomes are one of the main causes of habitual abortion. Partners, carrying equally balanced transposon chromosomes (a segment of DNA that is capable of independently replicating itself and inserting the copy into a new position within the same or another chromosome) are at greater risk of repeated abortions. However, if the sex chromosome develops abnormalities or becomes inverted this could also lead to habitual abortion. The woman examined by Xia and his colleagues was diagnosed as carrying equally balanced transposon chromosomes. She has lost no genetic material, so her body and brain developed normally. However, she experienced habitual abortion.
The discovery of abnormal chromosomes at Zhangzhou provides key data to help prevent the birth of infants with chromosome disease and improve the quality of the population. The discovery not only enriches the list of known chromosomal abnormalities, but will also help diagnose hereditary diseases and extend research into human DNA.
(China.org.cn by Wu Nanlan, December 11, 2002)
