The Turner Syndrome Society of the United States advances knowledge, facilitates research, and provides support for all touched by Turner syndrome. Turner syndrome (TS) is a chromosomal condition that describes girls and women with common features that are caused by complete or partial absence of the second sex chromosome. The syndrome is named after Dr. Henry Turner, who was among the first to describe its features in the 1930's. TS occurs in approximately 1 of every 2,000 female births. Diagnosis is made through a test called a karyotype, which is usually performed on cells in the amniotic fluid before birth, and on cells in the blood after birth.