• General considerations

• 1 out of every 2,000-2,500 female live births
• Almost all (95%) have
• Short stature
• Loss of ovarian function
• Caused by the absence of a set of genes from the short arm of one X chromosome
• Single X chromosome
• 75-80% single X is contributed by mother
• X-O = Female (Turner Syndrome)
• X-X-Y=Male (Klinefelter Syndrome)
• Hearing loss due to otosclerosis is common in adults

• Appearance

• Short stature
• Absent adolescent growth spurt
• Average adult height is 4 feet 8 inches
• Loss of SHOX gene necessary for growth of long bones
• Short fingers (4^th metacarpal)

Short 4th metacarpal in Turner Syndrome. A line (white line) drawn across the
heads of the 4th and 5th metacarpals will normally not transect a portion of the head of the 3rd
metacarpal unless the 4th metacarpal is short (see list below).

• Short toes
• Cubitus valgus – increased carrying angle (arms turn outward at elbow) the elbow
• Webbed neck
• Widely spaced nipples (shield crest)
• Excessive number of nevi
• Higher incidence of hip dislocation in infants
• Scoliosis in up to 10%
• Cutis laxa – loose folds of skin especially around neck

• Puberty and reproduction

• Loss of ovarian function usually in early childhood
• Delayed puberty
• Estrogen therapy is frequently used to induce changes of puberty

• Cardiovascular

• Coarctation of the aorta in 5-10%
• Bicuspid aortic valves in 15%
• Increased risk of aortic dissection
• Hypertension
• May be due to coarct or renal abnormalities or occur in absence of both

• Renal

• Horseshoe kidney

• Osteoporosis

• High incidence due to inadequate circulating estrogen

• Diabetes

• Type II (Insulin-resistant) diabetes
• Thyroid
• About 1/3 are hypothyroid, often with an enlarged thyroid

• Intelligence

• Normal intelligence