II. Epidemiology

  1. Incidence: 1 in 3000 live female births

III. Pathophysiology

  1. Partial or complete absence of one X-Chromosome
    1. Karyotype: 45,X
    2. Results in X-Chromosome genes that fail inactivation
      1. Expression of these genes causes Turner Phenotype
  2. Ovarian sex Hormone deficiency
    1. Due to congenitally fibrotic ovaries
    2. Results in lack of spontaneous pubertal development
  3. High spontanous Miscarriage rate
    1. Karyotype 45,X associated with 99% Miscarriage rate
    2. Turner's causes 10% of first trimester abortions
    3. No known risk factors and recurrence is rare

V. Signs: Fetus and infant

VI. Signs: Teen and older

  1. Majority of patients
    1. Short Stature
    2. Infantile female genitalia and Breasts
  2. More than 50% of patients have:
    1. High arched, narrow Palate with crowded teeth
    2. Eyelid Ptosis and infraorbital creases
    3. Webbed Neck
    4. Shield (broad) chest with widely spaced nipples
    5. Delayed Growth of axillary and pubic hair
    6. Hyperconvex nails
    7. Deformed or rotated ears
    8. Cubitus valgus
    9. Short Metacarpals (especially fourth)
    10. Congenital Lymphedema involving arms and legs
    11. Increased pigmented nevi
    12. Low posterior hairline

VII. Associated Conditions

  1. Cardiac malformation (33% of patients)
    1. Aortic Coarctation
    2. Bicuspid aortic valve
    3. Hypertension
  2. Strabismus
  3. Sensorineural Hearing Loss
  4. Recurrent Otitis Media
  5. Renal malformations (e.g. horseshoe Kidney)
  6. Autoimmune Thyroiditis
  7. Celiac Disease
  8. Congenital Hip Dysplasia
  9. Scoliosis

VIII. Labs

  1. Initial
    1. Karyotype
      1. Missing X Chromosome (45,X) in 50% of cases
    2. Follicle Stimulating Hormone
      1. Abnormally increased by age 14 years
    3. Buccal mucosa smear (historical interest only)
      1. Negative sex chromatin (male pattern)
  2. Annual
    1. Thyroid Stimulating Hormone (TSH)
    2. Liver Function Tests
    3. Fasting lipid profile
    4. Fasting Serum Glucose
  3. Other
    1. Tissue transglutaminase IgA (celiac) q2-4 years

IX. Imaging

  1. Chest XRay (initially)
    1. Aortic Coarctation
    2. Osteoporosis
  2. Echocardiogram
    1. Obtain initially at diagnosis
    2. Repeat q5-10 years to evaluate aortic root dilatation
  3. DEXA Scan
    1. Obtain baseline in adulthood
    2. Repeat periodically

X. Management: Children and Teens

  1. Genetic Consultation
  2. Congenital Heart Disease
    1. Initial Echocardiogram and Chest XRay
    2. Initial Blood Pressures in all 4 extremities
    3. Monitor and treat as needed
  3. Linear Growth Delay
    1. Consider Growth Hormone from age 1-2 to age 14
  4. Estrogen therapy
    1. Start in preteen years
    2. Promotes Sexual Development
    3. Prevents Osteoporosis
  5. Hearing evaluation
    1. Audiometry initially and monitoring periodically
  6. Vision evaluation
    1. Refer to pediatric ophthalmology after age 1
    2. Evaluate for Strabismus and Hyperopia
  7. Musculoskeletal evaluation
    1. Barlow and Ortolani Testing for hip dysplasia
    2. Evaluate for Scoliosis and kyphosis in teens
  8. Genitourinary evaluation
    1. Renal Ultrasound to assess for anomalies
  9. Dental evaluation
    1. Orthodontist evaluation for malocclusion

XI. Management: Women

  1. Fertility and Sexual Development
    1. Consult with gynecologic specialists
  2. Manage comorbid Coronary Risk Factors
  3. Osteoporosis Prevention
    1. Calcium and Vitamin D supplementation

XII. References

  1. Behrman (2000) Nelson Pediatrics, Saunders, p. 1753-4
  2. Wilson (1998) Williams Endocrinology, p. 1337-52
  3. Morgan (2007) Am Fam Physician 76:405-10 [PubMed]
  4. Saenger (2001) J Clin Endocrinol Metab 86(7):3061-9 [PubMed]

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