This study examines the clinical and genetic factors related to Turner syndrome, a disorder of the sex chromosomes. Humans usually have 23 pairs of chromosomes-thin strands of DNA-in the nucleus of every cell, which contain genes that determine our hereditary makeup. One pair of chromosomes is the sex chromosomes, designated X and Y. Females usually have two X chromosomes; however, patients with Turner syndrome have only a single X chromosome or one normal and one defective X or Y chromosome. This abnormality can cause medical problems such as short stature, premature ovarian failure and heart or kidney defects. Individuals with Turner syndrome have an increased risk of thyroid disorders, high blood pressure, diabetes mellitus, abnormal liver function, hearing loss and osteoporosis. This study will try to identify the genes responsible for the specific medical problems associated with the disorder.