• Pediatric Database (PEDBASE)
  • Discipline: GEN
  • Last Updated: 5/29/94
  • TURNER SYNDROME

    DEFINITION:

    A chromosomal disorder resulting in a syndrome characterized by specific dysmorphic features (short stature) and organ malforations (gonadal dysgenesis).

    EPIDEMIOLOGY:

    PATHOGENESIS:

    1. History

    2. Chromosomal Anomalies

    1. 45, XO karyotype

    2. 46, XX karyotype

    3. Mosaics

    3. Pathogenesis

    CLINICAL FEATURES:

    1. Classic

    2. Newborn

    3. Childhood/Adolescence

    4. Dysmorphic Features

    1. Eyes

    2. Ears

    3. Mouth

    4. Others

    5. Organ Malformations

    1. Cardiovascular

    1. Congenital Heart Malformations (20-30%)

  • 1. Coarctation of the Aorta (15-30%)
    • correlated with webbed neck
    • associated with hypertension
  • 2. Bicuspid Aortic Valve (33%)
    • predisposes to atherosclerotic disease
    • may stenose or calcify
    • should receive antibiotic prophylaxis
  • 3. Aortic Aneurysms
    • coarctation, hypertension, and aortic valve anomalies predispose to aneurysms
  • 4. Others
    • mitral valve prolapse (25%), ectopia cordis, hypoplastic left heart, pulmonary stenosis
  • 2. Vascular Malformations

    • generalized vascular dysplasia
    • intestinal telangiectasias:
      • gastrointestinal bleeding, protein-loosing enteropathy
    • others:
      • hemangiomas, venous ectasias, lymphangioectasia with chylous accumulation in chest & abdoman

    3. Lymphedema

    • dorsum of hands and feet - decreases during childhood
    • neck - cystic hygroma -> ear, neck & hairline changes

    4. Others

    • multiple renal arteries (90%)
    • hypertension: mild -> severe

    2. Genitourinary

    1. Structural Anomalies (33-60%)

    • 20% - double collecting system or absent kidney
    • 15% - malrotation
    • 10% - horseshoe kidneys
    • 6-10% - silent hydronephrosis
    • at risk for recurrent urinary tract infections, obstruction, hypertension

    3. Endocrine

    1. Short Stature

    • birth: mean length less than 48 cm
    • infancy: 3rd to 10th %
    • infancy -> puberty: 3rd % (with normal growth velocity)
    • adolescence : <3rd % (no growth spurt)
    • adult (untreated) : mean height = 144 cm (4'10")
    • will also get disproportionate increase in weight and delayed bone age (1-2 years)

    2. Fertility

    • rare but possible if undergo spontaneous puberty
    • mosaicism and deletions > 45, XO
    • greater number of miscarriages (50%)
    • " of congenital abnormalities (33%)

    3. Gonadal Dysgenesis/Failure

    • fibrotic ovarian streaks by birth:
      • degeneration of oocytes after 12 weeks in utero
      • accelerated transformation of ovaries to connective tissue
      • spontaneous puberty in 5-15% of cases
      • may have irregular periods & premature menopause after puberty

    4. Immune (Autoimmune)

    1. Hypothyroid (20-30%)

    • 50-60% have thryroid antibodies
    • higher risk of acute Hashimoto's thyroiditis and Graves' in isochromosome X

    2. Diabetes Mellitus (5%)

    • 25-60% have impaired glucose tolerance

    3. Others

    • inflammatory bowel disease (Crohn,s, Ulcerative Colitis) - increases with isochromosome X
    • rheumatoid arthritis

    INVESTIGATIONS:

    1. Diagnosis

    1. Karyotype

    2. Imaging Studies

    1. Skeletal Survey

    2. Cardiovascular Malformations

    3. Renal Malformations

    3. Serum

    MANAGEMENT:

    1. Supportive

    2. Surgery

    3. Endocrine

    1. Growth

    2. Gonadal Failure

    3. Fertility

    4. Hypothyroidism

    INTERNET LINKS:

    Turner's Syndrome Society of the United States
    The MAGIC Foundation