Effects of Karyotype Variations on Phenotype of Patients with Turner Syndrome

Background: Turner syndrome (TS) is a sporadic disorder caused by the absence of all or some parts one X-chromosome with major developmental consequences such as short stature and ovarian failure etc. The minor manifestations of TS are cubitus valgus, micrognatism, high-arched palate, short and/or webbed neck, hypothyroidism, etc. Different karyotype abnormalities may lead to different clinical features; therefore, in this study we have tried to postulate karyotype-phenotype correlations in these patients. Methods: In order to assess karyotype-phenotype correlations, 209 proven TS patients were studied and chromosomal analysis was performed on the basis of G-banding technique at high resolution. Results: According to cytogenetic findings, karyotype abnormalities were classified into four groups: classic form 19%; mosaic form 76%; long arm isochromosome 4% and short arm deletion 1%. Clinical manifestations were more severe in classic TS rather than the other forms of chromosomal abnormalities. Conclusion: The results of this study suggest that karyotype variations might affect phenotype of Turner syndrome. Therefore, chromosomal investigation for all suspected cases of Turner syndrome should be considered in order to approach an appropriate treatment protocol.