Functional glucocorticoid receptor gene variants do not underlie the high variability of 17-hydroxyprogesterone screening values in healthy newborns

Abstract

Objective: 17-Hydroxyprogesterone (17-OHP) screening for classical congenital adrenal hyperplasia (CAH) is part of many newborn screening programs worldwide. Cut-off values are relatively high, and screening sensitivity does not reach 100%. Recently, the glucocorticoid receptor (GR) N363S-variant has been linked to relatively low degree of virilization and comparatively lower 17-OHP serum concentrations in clinically diagnosed female CAH patients. We sought to determine whether functional GR gene variants, either increasing (N363S, BclI) or decreasing GR sensitivity (R23K), underlie the variable 17-OHP screening levels in healthy newborns. Design: GR genotypes were compared with 17-OHP screening values in 1000 random samples from routine screening. 17-OHP was measured by conventional immunoassay (TRFIA) and a liquid chromatography-tandem mass spectrometry method (LC-MS/MS), which has been shown to increase screening specificity by steroid profiling and avoiding cross-reactions of the 17-OHP-antibody. Results: There was no significant association of 17-OHP with GR genotypes, even after inclusion of gestational and postnatal age as covariates. However, among LC-MS/MS steroid measurements, we observed some unexpected trends, including lower 11-deoxycortisol concentrations in both 363S-and 23K-carriers. For carriers of the frequent BclI variant, linear regression analysis revealed a significant increase of 4-androstenedione levels with every mutant allele inherited. Conclusions: Functional GR variants do not underlie the variation of 17-OHP values observed in healthy individuals. However, whether and to which extent genetically determined differences in individual GR sensitivity influence 17-OHP screening levels in conditions of a pathological hypothalamus-pituitary-adrenal gland-axis stimulation and thus may explain false-negative screening results in those affected by CAH remains to be investigated.

Problems of neonatal screening on congenital adrenal hyperplasia

“…Ôåðìåíò ñïðèÿº ïåðåòâîðåííþ ïðîãåñòåðîíó íà äåçîêñèêîðòè-êîñòåðîí ³ 17-ã³äðîêñèïðîãåñòåðîíó íà 11-äå-çîêñèêîðòèçîë. Çàëåaeíî â³ä çáåðåaeåíî¿ àêòèâ-íîñò³ ôåðìåíòó ðîçð³çíÿþòü ñ³ëü-âòðàòíó ôîð-ìó (àêòèâí³ñòü 21-ã³äðîêñèëàçè º ìåíøîþ â³ä 1%), ïðîñòó â³ðèëüíó (àêòèâí³ñòü ôåðìåíòó íå ïåðåá³ëüøóº 5%), ï³çíþ íåêëàñè÷íó ôîðìó, ùî ìàí³ôåñòóº ï³ä ÷àñ ïóáåðòàòó àáî ó äîðîñëèõ (àêòèâí³ñòü ôåðìåíòó â ìåaeàõ 20-30%) [2,5,6,9,10]. Ç îãëÿäó íà àâòîñîìíî-ðåöåñèâíèé òèï óñïàäêóâàííÿ çàõâîðþâàííÿ íå äèâíî, ùî íà-éá³ëüøà ÷àñòîòà éîãî ðåºñòðóºòüñÿ â åòí³÷íî ³çîëüîâàíèõ ãðóïàõ, íà òåðèòîð³ÿõ ³ç ìàëîþ ê³ëü-ê³ñòþ íàñåëåííÿ, äå çá³ëüøåíî éìîâ³ðí³ñòü ïàðóâàííÿ îñ³á ³ç ãåòåðîçèãîòíèì íîñ³éñòâîì ìó-òàö³é ãåíà CYP21, ùî êîäóº ôåðìåíò 21-ã³äðîê-ñèëàçó.…”

“…Êîaeíó òðåòþ ä³â÷èíêó ç IV-V ñòóïåíåì â³ðèë³çàö³¿ çà Ïðàäåðîì [36] ËÅÊÖ²í àðîäaeåííÿ ðåºñòðóâàëè ó ÷îëîâ³÷³é ñòàò³. Â÷àñ-íî íå ä³àãíîñòîâàí³ â³ðèëüíà òà ï³çíÿ íåêëàñè÷-íà ôîðìè ÂÃÊÍÇ ñïðè÷èíÿëè ó ïàö³ºíò³â îáîõ ñòàòåé ã³ïåðàíäðîãåí³þ, çìåíøåííÿ ¿õ ê³íöåâî-ãî çðîñòó, ïîðóøåííÿ ñòàòåâîãî ðîçâèòêó òà íåïë³äí³ñòü, ó ä³â÷èíîê òà ¿õ áàòüê³â -ïñèõîëî-ã³÷í³ ïðîáëåìè, ïîâ'ÿçàí³ ç âèðàaeåíèì ã³ðñóòèç-ìîì ³ íàâ³òü íåîáõ³äí³ñòþ çì³íè ñòàò³ äèòèí³ ç êàð³îòèïîì 46ÕÕ (ó ðàç³ ïîïåðåäíüî¿ ¿¿ ðåºñòðà-ö³¿ ó ÷îëîâ³÷³é ñòàò³ âíàñë³äîê âðîäaeåíî¿ ã³ïåð-àíäðîãåí³¿) [2,5,9,10,21,25,40,45]. Çã³äíî ç âëàñíèìè äàíèìè, ñåðåä 48 ä³â÷èíîê ³ç ÂÃÊÍÇ, ÿê³ ïðîõîäèëè ë³êóâàííÿ ç 2007 ïî 2012 ðîêè, ø³ñòüîõ (12,5%) áóëî çàðåºñòðîâàíî íà ÷àñ íà-ðîäaeåííÿ ó ÷îëîâ³÷³é ñòàò³, ñïðàâaeíþ ñòàòü áóëî âñòàíîâëåíî ëèøå ï³ä ÷àñ ãîñï³òàë³çàö³¿ ó â³ää³-ëåííÿ.…”

“…Ðàçîì ³ç òèì, çà äàíèìè çâ³ò³â îáëàñíèõ äèòÿ÷èõ åí-äîêðèíîëîã³â 2011 ðîêó, òàêèõ ä³òåé íàë³÷óâà-ëîñÿ ëèøå 85. ×àñòîòà ï³çíüî¿ ôîðìè ÂÃÊÍÇ âíàñë³äîê äåô³öèòó 21-ã³äðîêñèëàçè, çà äàíèìè íèçêè àâòîð³â, ñêëàäຠ0,1-1% ó çàãàëüí³é ïîïó-ëÿö³¿ [2,5,6,9,10,21,49]. Îòaeå, ñåðåä ä³òåé Óêðà¿íè ìຠáóòè â³ä 800 äî 8000 õâîðèõ ³ç ö³ºþ íîçîëî㳺þ.…”

“…Óñ³ êîíòðîëüí³ âè-ì³ðþâàííÿ 17-ÎÍÐ ìàþòü îö³íþâàòèñÿ çà íîð-ìàòèâíèìè ïîêàçíèêàìè ëàáîðàòîð³¿, äå âèêî-íóºòüñÿ àíàë³ç [2,9]. Çà äàíèìè ãîðìîíàëüíèõ ëàáîðàòîð³é Óêðà¿íè, íîðìàëüíèé ð³âåíü 17-ÎÍÐ ó äîíîøåíèõ íåìîâëÿò ç 5-ãî äî 60-ãî äíÿ â³ä íàðîäaeåííÿ ó ñèðîâàòö³ êðîâ³ íå ïåðåâèùóº 5 íã/ìë.…”

“…Òàê, äëÿ ñ³ëü-âòðàòíî¿ ôîðìè õàðàêòåðíîþ º íàÿâ-í³ñòü äåëåö³é ³ çíà÷íèõ ãåííèõ êîíâåðñ³é (Q318X, R356W, 12 spl), äëÿ â³ðèëüíî¿ ôîðìè -òî÷êîâî¿ ìóòàö³¿ I172N. Òî÷êîâ³ ìóòàö³¿ V281L, P30L, P453S º õàðàêòåðíèìè òàêîae äëÿ íåêëàñè÷íî¿ ôîðìè ÂÃÊÍÇ [1,2,3,5,9,10,22,23,35,45]. Àëå ç îãëÿäó íà âåëèêó ê³ëüê³ñòü ôåðìåíò³â, ùî áå-ðóòü ó÷àñòü ó ñòåðî¿äî´åíåç³, çíà÷íó ê³ëüê³ñòü âàð³àíò³â ìóòàö³é òà ¿õ êîìá³íàö³é íå äèâíî, ùî ó ñâ³ò³ êîaeí³ 2-3 ðîêè â÷åí³ â³äêðèâàþòü íîâ³ ãåíí³ ìóòàö³¿, ÿê³ ïðèçâîäÿòü äî óðàaeåííÿ êîðè ÍÇ ³ç ðîçâèòêîì ð³çíèõ ôîðì ¿¿ äèñôóíêö³¿.…”