Clinical and Cytogenetic Evaluation of a Case with Mosaic 45,X/46,X,i(Y) Karyotype

Abstract

Turner syndrome (TS) is a chromosomal disorder that affects only females and is typically characterized by a 45, X karyotype. In addition to the classic form, TS may present with various karyotypes. In this study, we report a rare mosaic karyotype, 45, X/46, X, i(Y)(p), identified in an 8-year-old girl who was referred for evaluation due to a preliminary diagnosis of TS. Conventional cytogenetic and FISH analyses revealed that 80% of the cells harbored an isochromosome Yp structure containing the SRY gene but lacking the Yq12 region. The clinical phenotype was completely female, and no follicles were observed in the ovaries on pelvic ultrasound. Due to the presence of Y chromosomal material, the patient was evaluated for the risk of gonadoblastoma and underwent prophylactic gonadectomy. This rare case highlights the importance of utilizing both karyotyping and FISH analysis in the diagnostic evaluation of Turner syndrome.Moreover, the case may also be considered within the spectrum of mixed gonadal dysgenesis (MGD), emphasizing the need for careful clinical and cytogenetic assessment.

Keywords

• Turner syndrome
• isochromosome
• karyotype
• FISH (Fluorescence ın situ hybridization)

References

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