Meta-analysis of 465 Cases of 17α-Hydroxylase/17,20-Lyase Deficiency (17-OHD)

Overview

This meta-analysis of 465 patients with 17-OHD reveals that homozygous CYP17A1 variants cause a spectrum of clinical features including hypertension, hypokalemia, and disorders of sexual development. More severe variants correlate with hypocortisolism and combined hypokalemia and hypertension, highlighting genotype-phenotype relationships.

Background

17α-Hydroxylase/17,20-lyase deficiency (17-OHD) is a rare form of congenital adrenal hyperplasia caused by pathogenic variants in the CYP17A1 gene, leading to impaired steroidogenesis. This enzyme defect disrupts cortisol and sex steroid synthesis, resulting in hypertension, hypokalemia, and sexual development disorders. Variants cluster ethnically and cause either complete or partial enzyme deficiency, influencing clinical severity. Understanding genotype-phenotype correlations is essential for diagnosis and management.

Data Highlights

Key Findings

• Homozygous CYP17A1 variants were present in nearly half (48%) of patients, often associated with more severe clinical features.
• Hypertension (57%) and hypokalemia (45%) were common presenting features due to mineralocorticoid excess.
• Disorders of sexual development were frequent, including primary amenorrhea (38%), cryptorchidism (15%), and atypical genitalia (14%).
• The p.Y329Kfs variant was the most frequent and linked to hypocortisolism, combined hypokalemia and hypertension, and sexual development abnormalities.
• Male patients were typically diagnosed earlier due to genital dysplasia, while female patients were diagnosed later, often presenting with primary amenorrhea and hypertension.
• Genotype-phenotype correlations indicate that more severe variants cause combined enzyme deficiencies and more pronounced clinical manifestations.

Clinical Implications

Clinicians should consider 17-OHD in patients presenting with hypertension and disordered sexual development, especially in the presence of hypokalemia. Early genetic testing for CYP17A1 variants can aid diagnosis and guide management. Awareness of variant-specific phenotypes may improve prognostication and individualized care.

Conclusion

This large meta-analysis clarifies the genotype-phenotype spectrum of 17-OHD, emphasizing the importance of recognizing clinical features linked to specific CYP17A1 variants. Improved understanding facilitates earlier diagnosis and tailored treatment strategies.

References

1. Meta-analysis of Documented Cases of 17α-Hydroxylase/17,20-Lyase Deficiency (17-OHD), 2023