Karyotype showing the arrangement of chromosomes in a female with Turner's syndrome (X0). Turner's syndrome, which only affects women, is an absence of the second sex chromosome. In a healthy woman there would be two X chromosomes instead of one (seen at lower right). The symptoms of Turner's syndrome include stunted growth, retarded sexual development (leading to infertility), and webbing of the skin of the neck. Often heart problems are present too. Turner's syndrome is rare, affecting around one in every 3000 female births. The normal chromosome count is 46, 23 from maternal and 23 from paternal origin. Unlabelled computer illustration