Effects of growth hormone and sex steroid therapy on brain structure and pituitary function in turner syndrome

Abstract

Introduction: Turner syndrome (TS) is a chromosomal disorder affecting approximately 1 in 2,500 live female births, characterized by the partial or complete absence of one X chromosome. This genetic anomaly leads to physical, cognitive, and endocrine abnormalities, including short stature, gonadal dysgenesis, and structural brain anomalies. Cognitive deficits in TS involve visuospatial processing, memory, and executive function, often linked to structural brain changes. Magnetic resonance imaging (MRI) has revealed significant alterations in gray and white matter volumes in various brain regions. Growth hormone (GH) and sex steroid therapies, such as estrogen and progesterone, are used to address growth and developmental delays in TS. However, their impact on brain structure and pituitary function remains an area of active research. Aim of the Review: To systematically review and synthesize findings on the effects of GH and sex steroid therapy on brain structure and pituitary function in patients with Turner syndrome. Methods: A comprehensive literature review was conducted to identify studies examining the effects of GH and sex steroid therapy on brain structure and pituitary function in TS. Data from various sources were compiled, focusing on MRI-based structural brain changes. Key parameters analyzed included sample size, findings from MRI and fMRI studies, and clinical associations. Studies were summarized and presented in a structured table format. Results: Estrogen-progesterone treatment was found to suppress pituitary gonadotropin release more effectively than estrogen alone, indicating a feedback interaction between pituitary gonadotropin release and sex steroids. MRI studies showed that TS patients exhibit smaller volumes in the hippocampus, caudate, lenticular, thalamic nuclei, and parieto-occipital brain matter, correlating with cognitive deficits. GH-IGF axis abnormalities are modulated by body composition and physical fitness, with sex hormone replacement normalizing the GH-IGF axis and improving body composition. Although GH therapy alone did not significantly improve cognitive functions, the combination of GH with oxandrolone improved working memory. Estrogen deficiency and TS are associated with slower growth in parieto-occipital regions and enhanced volume growth in basal ganglia and cerebellar areas during adolescence, underscoring the importance of estrogen replacement in brain development. Discussion: GH and sex steroid therapies significantly impact brain structure, pituitary function, and clinical outcomes in TS. GH therapy, often combined with sex steroids, improves growth and cognitive functions, particularly working memory. However, GH alone does not significantly impact overall cognitive function. The timing and combination of these therapies are crucial for optimizing outcomes. Regular monitoring and individualized treatment plans are essential to address the complex needs of TS patients. Further research is needed to explore the long-term impacts of these therapies and develop optimal treatment regimens. Conclusion: GH and sex steroid therapies are vital in managing TS contributing to improved growth, body composition, and cognitive enhancements. A multifaceted therapeutic approach and regular monitoring are crucial for optimizing treatment outcomes and quality of life for TS patients.