Female mosaicism of the X chromosome has major implications for human health and disease and is the leading cause of female protection from X-linked genetic disorders.
女性作为X染色体的杂合子在人类的健康与疾病中及重要作用，并可避免X连锁遗产性疾病在女性中发生。
2
Currently, we are able to perform PGD for many genetic conditions including single gene disorders and chromosome abnormalities.
目前，使用PGD技术，可以测试出许多种不同的疾病，包括非整倍体，单基因病和染色体易位等。
3
Ultrasonography alone does not determine if a pregnancy has Down syndrome or other chromosomedisorders;