A rare CYP 21 mutation (p.E431K) induced deactivation of CYP 21A2 and resulted in congenital adrenal hyperplasia

Endocrine Journal

Keiichi Hanaki¹  Susumu Kanzaki²  Masanobu Fujimoto²  Rei Nishimura²  Yuki Kawashima²  Naoki Miyahara²  Takeshi Usui³ 

[1] Department of Women’s and Children’s Family Nursing, Tottori University Faculty of Medicine, Yonago 683-8504, Japan;Division of Pediatrics & Perinatology, Tottori University Faculty of Medicine, Yonago 683-8504, Japan;Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan

关键词: Congenital adrenal hyperplasia;    21-hydroxylase deficiency;    CYP21A2;   

DOI  :  10.1507/endocrj.EJ14-0437

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(19)Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is caused by mutations in the CYP21A2 gene.The residual enzyme activity is strongly associated with the phenotype.We describe a rare case of CAH with a rare CYP21A2 mutation.The patient was a one-year-old Japanese boy.At 16 days old, he was referred to our hospital because of elevated serum 17-OH-progesterone (17-OHP) levels in neonatal screening.The compound heterozygous mutations (IVS2-13 A/C>G, and p.E431K) in CYP21A2 were identified at 2 months old, and we diagnosed non-classical CAH, since he did not have significant physical signs (pigmentation and salt-wasting).However, his body weight decreased, and his serum 17-OHP level (99.5 ng/mL) was elevated at 3 months old.Steroid replacement therapy was started at 3 months old.Our patient’s clinical course resembled simple virilizing (SV) CAH, but classification was difficult because the patient showed increased renin activity indicating an aldosterone deficiency, and late onset of symptoms.While the IVS 2-13 A/C>G mutation is common in the classical form of CAH, p.E431K is a rare point mutation.Functional analysis revealed that the residual enzyme activity of p.E431L was 5.08±2.55% for 17-OHP and 4.12±2.37% for progesterone, which is consistent with SV CAH.p.E431 is localized in the L-helix near the heme-binding site.The mutation might interfere with heme binding, leading to deactivation of CYP21A2.This report showed that CYP21A2 p.E431 has an important effect on enzyme activity.

【 授权许可】

Unknown