Turner Syndrome and Its Variants

Abstract

Turner syndrome (TS) is a genetic disorder which is characterized by the complete or partial absence of the X chromosome. The incidence is 1/2500 female live births. The main clinical findings are short stature, primary amenorrhea and infertility, and phenotypical features include webbed neck, a low posterior hairline, cubitus valgus and shortening of the fourth metacarpal. While 1% of all still births have 45,X monosomy, this rate has been reported to be approximately 10% in spontaneous abortions. The karyotype is determined as 45,X in about half of the patients. Therefore, most of the TS fetuses are considered to end in spontaneous abortion and only mosaic cases survive to term. Isochromosome Xq is the most common structural rearrangement of the X chromosome. Furthermore, ring X chromosome, deletions and Y chromosome abnormalities can be detected in patients with TS.

Keywords

• Turner syndrome
• mosaicism
• isochromosome
• ring chromosome
• short stature