Turner Syndrome

Overview

Introduction

• Monosomy resulting from 
  • nondisjuction (XO) 
  • mosaicism (XX, XO; XY, XO) 
  • only monosomy not aborted in utero
  • no Barr bodies
• Leads to abnormal sexual differentiation with 
  • primary amenorrhea
  • streak gonads   
    • menopause before menarche
  • infertility
  • delayed sexual maturation
  • normal intellegence
• Pathogenesis
  • ↓ estradiol leads to ↑ FSH and LH 
• normal GH and insulin-like growth factor

Presentation

• Physical exam 
  • short stature
  • webbed neck
  • shield chest 
  • wrist and ankle edema
• both edema and webbed neck a result of malformed lymphatic vasculature  

Prognosis, Prevention, and Complications

• Increased risk for
  • gonadal blastoma (specifically XY, XO mosaics, as Y chromosome increases risk of tumor formation in dysgenic gonads)
  • preductal coarctation of aorta and bicuspid aortic valve 
  • dysgerminoma ovarian tumor
  • horseshoe kidney
• decreased fertility