Turner Syndrome

Short stature is usually present in females with Turner syndrome. This is partially due to a loss of the SHOX gene, which encodes a protein important for long bone growth. The height in adults with Turner syndrome ranges from 143-145 cm (approximately 4 ft 8 in). Treatment using growth hormones during early childhood development can increase growth by a few inches in some cases. The loss of the X-chromosome genes may also be related to the intrauterine growth retardation, a gradual decline in growth rate during childhood, and the absence of a pubertal growth spurt. Females with Turner syndrome have abnormal body proportions characterized by markedly shortened lower extremities.

Lost X-chromosome genes that are involved in the regulation of ovarian development and function results in a failure of individuals with Turner syndrome to enter into puberty at a normal age. Although 10% of females with Turner syndrome will go through puberty spontaneously, most will require hormone therapy for development of secondary sexual characteristics and menstruation. Without hormonal intervention, most teenagers that undergo partial breast development and menstruate spontaneously will eventually cease further development and menstruation. A few pregnancies have been reported and most likely occur prior to ovarian failure. The time of initiation of therapy varies with each female but usually begins no later than 15 years of age. Various estrogenic and progestational agents and schedules have been used as hormone therapy to maintain their secondary sexual development and prevent osteoporosis (bone degradation) later in life. Although most women with Turner syndrome do not have functional ovaries, pregnancy may be possible through in vitro fertilization (assisted reproductive technology).

Renal abnormalities occur in 1/3 to 1/4 of females with Turner syndrome. The most common abnormality is a horseshoe kidney. Cardiac abnormalities are also common, with the coarctation of the aorta being the most common defect. This is a condition that results from a severe constriction a major blood vessel in the heart, can be treated with surgery, and occurs in 5-10% of affected children. Turner syndrome females generally have normal intelligence, however, most may exhibit learning disabilities, especially with regard to spatial perception, visual-motor coordination, and mathematics. As a result, the nonverbal IQ in Turner syndrome tends to be lower, with a relatively normal verbal IQ. Females with Turner syndrome may also be socially immature for their age and may need support in developing independence and social relationships.