The diagnosis of nonclassic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, based on serum basal or post-ACTH stimulation 17-hydroxyprogesterone, can lead to false-positive diagnosis.
OBJECTIVE
As nonclassic congenital adrenal hyperplasia (NCCAH) needs to be taken into account in women with hyperandrogenism, we aimed to assess whether the recommended level of poststimulated 17OHP ≥30 nmol/l confirms NCCAH.


METHODS
Forty, consecutive women with biochemical and/or clinical hyperandrogenism (aged 25·4, 18-38) suspected of having NCCAH were recruited to the study. In patients with 17OHP level between 5·1 and 29·9 nmol/l an ACTH stimulation test was performed. In patients with basal or poststimulated 17OHP ≥30 nmol/l, twenty-four-hour urinary steroid profile (USP) analysis was performed and CYP21A2 mutation was assessed. In selected patients with poststimulated 17OHP <30 nmol/l USP was also performed.


RESULTS
The group was divided into two subgroups with basal or poststimulated 17OHP ≥30 nmol/l (group A) and with poststimulated 17OHP <30 nmol/l (group B). Among 40 patients, basal or poststimulated 17OHP ≥30 nmol/l was found in 21, but NCCAH was confirmed by USP followed by genetic testing only in 5 (24%). Four patients were diagnosed as heterozygotes, and in twelve, no CYP21A2 mutation was detected.


CONCLUSIONS
The diagnosis of NCCAH based only on serum 17OHP measurements (basal or poststimulated) may lead to false-positive diagnosis when performed by immunoassay with a cut-off value of ≥30 nmol/l. The definitive diagnosis can be established based on USP and/or genetic testing.
Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland.
Urszula
U
Ambroziak
Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland.
Anna
A
Kępczyńska-Nyk
Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland.|Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
Alina
A
Kuryłowicz
Department of Biochemistry, Radioimmunology and Experimental Medicine, Children's Memorial Health Institute, Warsaw, Poland.
Ewa Maria
EM
Małunowicz
Genomic Medicine, Medical University of Warsaw, Warsaw, Poland.|Laboratory of Human Cancer Genetics, Centre of New Technologies, CENT, University of Warsaw, Warsaw, Poland.
Anna
A
Wójcicka
Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland.
Piotr
P
Miśkiewicz
Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland.
Magdalena
M
Macech
D019326:17-alpha-Hydroxyprogesterone / Q000097:blood*; D000293:Adolescent; D000304:Adrenal Cortex Function Tests; D000312:Adrenal Hyperplasia, Congenital / Q000097:blood* / Q000175:diagnosis* / Q000235:genetics; D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage; D000328:Adult; D005260:Female; D005820:Genetic Testing; D006801:Humans; D017588:Hyperandrogenism / Q000097:blood / Q000175:diagnosis; D009154:Mutation; D012016:Reference Values; D012680:Sensitivity and Specificity; D013255:Steroid 21-Hydroxylase / Q000235:genetics / Q000378:metabolism*; D013256:Steroids / Q000652:urine; D055815:Young Adult
D013256:Steroids; D019326:17-alpha-Hydroxyprogesterone; D000324:Adrenocorticotropic Hormone; D013255:Steroid 21-Hydroxylase