17-Hydroxyprogesterone Response to Standard Dose Synacthen Stimulation Test in CYP21A2 Heterozygous Carriers and Non-carriers in Symptomatic and Asymptomatic Groups: Meta-analyses

INTRODUCTION: Standard dose synacthen stimulation test (SDSST) is a gold standard screening test for evaluating adrenal gland function. Despite studies using SDSST to identify heterozygosity in CYP21A2, the reliability of the test for this purpose is still controversial. Therefore, the meta-analyses were performed to determine the differences in 17-hydroxyprogesterone (17-OHP) responses to standard dose (0.25 mg) SDSST in the diagnosis of CYP21A2 heterozygous individuals, with or without clinical signs of androgen excess disorders.
METHODS: PubMed and MEDLINE databases were searched. A total of 1215 subjects (heterozygous carriers n=669, mutation-free controls n=546) were included in the meta-analyses.
RESULTS: Basal 17-OHP median/mean levels were 4.156 (3.05-10.5)/5.241 (±2.59) nmol/L and 3.90 (2.20-9.74)/4.67 (±2.62) nmol/L in symptomatic heterozygous carriers and symptomatic mutation-free controls, respectively. Stimulated 17-OHP median/mean levels were 17.29 (14.22-37.2)/19.51 (±7.63) nmol/L and 9.27 (7.32-15.9)/10.77 (±3.48) nmol/L in symptomatic heterozygous carriers and symptomatic mutation-free controls, respectively. Basal 17-OHP median/mean levels were 3.21 (2.64-4.78)/3.33 (±0.84) nmol/L and 3.12 (1.82-3.6)/2.83 (±0.71) nmol/L in asymptomatic heterozygous carriers and asymptomatic mutation-free healthy controls, respectively. Stimulated 17-OHP median/mean levels were 14.16 (12.73-16.37)/14.16 (±1.37) nmol/L and 6.26 (4.9-8.23)/6.48 (±1.2) nmol/L in asymptomatic heterozygous carriers and asymptomatic mutation-free healthy controls, respectively. The cut-off levels for stimulated 17-OHP were 10.48 nmol/L and 13.48 nmol/L for asymptomatic heterozygous and symptomatic heterozygous, respectively.
DISCUSSION AND CONCLUSION: The meta-analyses support the idea that stimulated 17-OHP level has potential for use in identifying CYP21A2 carriers. Besides, considering differences in the basal and stimulated 17-OHP levels in symptomatic heterozygous individuals compared to those who were asymptomatic heterozygous could increase the accuracy of the test.