Turner Syndrome.

Area of Science:

• Genetics
• Endocrinology
• Reproductive Medicine

Background:

• Turner syndrome (TS) is a chromosomal disorder affecting phenotypic females, characterized by the absence of all or part of a second sex chromosome.
• First described a century ago, its cytogenetic basis was established in 1959.
• TS presents with a range of karyotypes, including monosomy X, mosaicism, isochromosome X, and ring X.

Purpose of the Study:

• To review the clinical indications for genetic testing in Turner syndrome.
• To describe various cytogenetic test methodologies for diagnosing TS.
• To summarize clinical management options and discuss age-related sex chromosome loss.

Main Methods:

• Review of existing literature on Turner syndrome.
• Analysis of cytogenetic data and karyotype variations.
• Compilation of clinical phenotypes and management guidelines.

Main Results:

• TS karyotypes are diverse, with monosomy X being the most common (40%-50%).
• The paternal X chromosome is absent in approximately 75% of TS cases, though parental origin is not clinically relevant for routine care.
• Common postnatal phenotypes include short stature, delayed puberty, ovarian dysgenesis, infertility, and associated medical conditions.

Conclusions:

• Turner syndrome diagnosis relies on identifying specific X chromosome abnormalities.
• Management involves addressing short stature, pubertal delay, and associated medical comorbidities.
• Understanding TS karyotype complexity is crucial for accurate diagnosis and tailored patient care.