Characterization of a novel CYP19A1 (aromatase) R192H mutation causing virilization of a 46,XX newborn, undervirilization of the 46,XY brother, but no virilization of the mother during pregnancies.

Bouchoucha, Nadia; Samara-Boustani, Dinane; Pandey, Amit Vikram; Bony-Trifunovic, Helene; Hofer, Gaby; Aigrain, Yves; Polak, Michel; Flück, Christa (2014). Characterization of a novel CYP19A1 (aromatase) R192H mutation causing virilization of a 46,XX newborn, undervirilization of the 46,XY brother, but no virilization of the mother during pregnancies. Molecular and cellular endocrinology, 390(1-2), pp. 8-17. Elsevier Ireland 10.1016/j.mce.2014.03.008

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BACKGROUND P450 aromatase (CYP19A1) is essential for the biosynthesis of estrogens from androgen precursors. Mutations in the coding region of CYP19A1 lead to autosomal recessive aromatase deficiency. To date over 20 subjects have been reported with aromatase deficiency which may manifest during fetal life with maternal virilization and virilization of the external genitalia of a female fetus due to low aromatase activity in the steroid metabolizing fetal-placental unit and thus high androgen levels. During infancy, girls often have ovarian cysts and thereafter fail to enter puberty showing signs of variable degree of androgen excess. Moreover, impact on growth, skeletal maturation and other metabolic parameters is seen in both sexes. OBJECTIVE AND HYPOTHESIS We found a novel homozygous CYP19A1 mutation in a 46,XX girl who was born at term to consanguineous parents. Although the mother did not virilize during pregnancy, the baby was found to have a complex genital anomaly at birth (enlarged genital tubercle, fusion of labioscrotal folds) with elevated androgens at birth, normalizing thereafter. Presence of 46,XX karyotype and female internal genital organs (uterus, vagina) together with biochemical findings and follow-up showing regression of clitoral hypertrophy, as well as elevated FSH suggested aromatase deficiency. Interestingly, her older brother presented with mild hypospadias and bilateral cryptorchidism and was found to carry the same homozygous CYP19A1 mutation. To confirm the clinical diagnosis, genetic, functional and computational studies were performed. METHODS AND RESULTS Genetic analysis revealed a homozygous R192H mutation in the CYP19A1 gene. This novel mutation was characterized for its enzymatic activity (Km, Vmax) in a cell model and found to have markedly reduced catalytic activity when compared to wild-type aromatase; thus explaining the phenotype. Computational studies suggest that R192H disrupts the substrate access channel in CYP19A1 that may affect binding of substrates and exit of catalytic products. CONCLUSION R192H is a novel CYP19A1 mutation which causes a severe phenotype of aromatase deficiency in a 46,XX newborn and maybe hypospadias and cryptorchidism in a 46,XY, but no maternal androgen excess during pregnancy.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of General Internal Medicine (DAIM) > Clinic of General Internal Medicine
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Unit Childrens Hospital > Forschungsgruppe Endokrinologie / Diabetologie / Metabolik (Pädiatrie)

UniBE Contributor:

Bouchoucha, Nadia; Pandey, Amit Vikram; Hofer, Gaby and Flück, Christa

Subjects:

600 Technology > 610 Medicine & health
500 Science > 570 Life sciences; biology

ISSN:

0303-7207

Publisher:

Elsevier Ireland

Funders:

[4] Swiss National Science Foundation

Projects:

[102] Pathogenesis of disorders caused by human P450 oxidoreductase mutations Official URL

Language:

English

Submitter:

Amit Vikram Pandey

Date Deposited:

09 Oct 2014 10:15

Last Modified:

22 Sep 2016 09:05

Publisher DOI:

10.1016/j.mce.2014.03.008

Related URLs:

PubMed ID:

24705274

Uncontrolled Keywords:

Aromatase, CYP19A1, DSD, Disorder of sexual development, Fetal–placental unit, Steroidogenesis

BORIS DOI:

10.7892/boris.51612

URI:

https://boris.unibe.ch/id/eprint/51612

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