Hormonal evaluation and mutation screening for steroid 21-hydroxylase deficiency in patients with unilateral and bilateral adrenal incidentalomas.
OBJECTIVE
The aims of the present study were (a) to examine the occurrence of 21-hydroxylase gene (CYP21) mutations in patients with unilateral and bilateral adrenal incidentalomas and (b) to correlate the results of mutation screening with hormonal parameters of 21-hydroxylase deficiency.


METHODS
The frequency of the eight commonly occurring CYP21 mutations in blood DNA samples of 19 patients with bilateral, as well as in blood and tumoral tissue DNA samples of 31 patients with unilateral adrenal incidentalomas, was determined. In all patients, hormonal evaluation for 21-hydroxylase deficiency was performed using measurements of basal and ACTH-stimulated plasma 17-hydroxyprogesterone (17-OHP) concentrations.


METHODS
Blood and tumoral DNA samples were analyzed by allele-specific PCR for the detection of the eight commonly occurring CYP21 mutations (deletion/large gene conversion, intron 2 splicing, Ile172Asn, exon 6 cluster, Val281Leu, Leu307insT, Gln318Stop and Arg356Trp mutations). Plasma 17-OHP concentrations were measured by radioimmunoassay.


RESULTS
Of the 19 patients with bilateral adrenal incidentalomas, one patient had homozygous (Val281Leu) and three patients had heterozygous germline CYP21 mutations (Val281Leu in two cases and Arg356Trp in one case). Heterozygous germline CYP21 mutations were also detected in five of the 31 patients with unilateral adrenal incidentalomas (Ile172Asn in three cases and Val281Leu in two cases). Mutation screening of tumoral DNA in unilateral incidentalomas showed the presence of corresponding germline mutations but no additional somatic mutations were found. ACTH-stimulated plasma 17-OHP concentrations were above 1500 ng/dl in all patients with bilateral incidentalomas who had homozygous and heterozygous CYP21 mutations, but heterozygous carriers with unilateral incidentalomas had highly variable ACTH-stimulated plasma 17-OHP levels (between 111 and 1705 ng/dl).


CONCLUSIONS
These results suggest a similar frequency of germline CYP21 mutations in patients with bilateral and unilateral adrenal incidentalomas (21.1% and 16.1% respectively). Therefore, it cannot be ruled out that, in at least some patients, CYP21 mutations may play a role in the pathomechanism of bilateral and unilateral adrenal incidentalomas. However, the lack of clear association of CYP21 mutations with increased ACTH-stimulated plasma l7-OHP response, especially in patients with unilateral incidentalomas, suggests that the effect of CYP21 mutations on adrenocortical tumor formation may also involve mechanism(s) independent of ACTH-induced changes in 17-OHP secretion.
Patócs
Attila
A
2nd Department of Medicine, Faculty of Medicine, Semmelweis University, H-1088 Budapest, Hungary.
Tóth
Miklós
M
Barta
Csaba
C
Sasvári-Székely
Mária
M
Varga
Ibolya
I
Szücs
Nikolette
N
Jakab
Csilla
C
Gláz
Edit
E
Rácz
Károly
K
D019326:17-alpha-Hydroxyprogesterone / Q000097:blood; D000236:Adenoma / Q000097:blood / Q000235:genetics*; D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000235:genetics*; D000312:Adrenal Hyperplasia, Congenital; D000324:Adrenocorticotropic Hormone; D000483:Alleles; D004247:DNA / Q000032:analysis / Q000097:blood; D004252:DNA Mutational Analysis; D005260:Female; D006728:Hormones / Q000097:blood*; D006801:Humans; D007438:Introns; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D013255:Steroid 21-Hydroxylase / Q000235:genetics*
D006728:Hormones; D019326:17-alpha-Hydroxyprogesterone; D000324:Adrenocorticotropic Hormone; D004247:DNA; D013255:Steroid 21-Hydroxylase