Endocrine profile and phenotype-genotype correlation in unrelated patients with non-classical congenital adrenal hyperplasia Nicos Skordis a, b, ⁎, Christos Shammas b , Elisavet Efstathiou a , Katerina Kaffe b , Vassos Neocleous b , Leonidas A. Phylactou b a Paediatric Endocrine Unit, Makarios III, Hospital, Nicosia, Cyprus b The Cyprus Institute of Neurology and Genetics, Dept of Molecular Genetics, Function & Therapy, 1683, Nicosia, Cyprus abstract article info Article history: Received 24 February 2011 Received in revised form 6 May 2011 Accepted 11 May 2011 Available online 24 May 2011 Keywords: NC-CAH CYP21A2 17-OHP Testosterone Δ4 Objectives: The aim of this study was to identify the molecular defect in a group of 37 unrelated Greek Cypriot patients affected by NC-CAH and evaluate the relationship between the genotype, phenotype and adrenal androgen levels. Design and methods: Clinical evaluation, biochemical analysis of 17-OHP, Testosterone, Androstenedione, DHEA-S, direct DNA sequencing and MLPA analyses. Results: Eleven known mutations were identified with the p.V281L being the most predominant and observed in 68.9% of the alleles. There was no difference between the two genotypes (mild/mild and mild/severe) with clinical presentation, whereas a proportional relationship between the type of mutation and adrenal androgen levels was found. Conclusion: The frequency of the underlying genetic defect in our patients with NC-CAH is similar to that observed in most Mediterranean populations. Although the genotype cannot solely explain the clinical expression of NC-CAH, discrimination between mild and severe alleles is crucial in antenatal diagnosis and genetic counselling. © 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Introduction Congenital adrenal hyperplasia (CAH) is a recessively inherited disorder which is caused by the loss or severe decrease in the activity of one of the enzymatic steps required for cortisol biosynthesis in the adrenal cortex. The most common form of CAH (95% of all cases) is due to 21-OHD resulting from molecular defect in the steroid 21- hydroxylase (CYP21A2) gene, with an overall estimated incidence of 1:10,000 to 1:15,000 for the severe classic form and 1:500 to 1:100 live births for the NC-CAH [1–8]. The CYP21A2 gene is located on the short arm of chromosome 6, within the region of the major histocompatibility complex (MHC), at a distance of 30 kb from a highly homologous (N 95%) pseudogene, designated CYP21A1P. Most mutations in 21-OHD deficiency result from the transfer of sequences between the CYP21P pseudogene and the active CYP21A2 gene. The known defects of the CYP21A2 gene that result in the different forms of 21-OHD deficiency are deletions, conversions and more than 100 alleles have been identified in patients with CAH (Human Gene Mutation Database: http://www. hgmd.cf.ac.uk/ac/index.php) [6,9–13]. NC-CAH due to 21–OHD initially reported by Decourt et al. represents nowadays a common endocrine disorder in certain ethnic groups especially in the Mediterranean region [14,15]. Patients with NC-CAH have no evidence of ACTH excess and generally present with signs and symptoms of androgen excess rather than symptoms reflecting glycocorticoid deficiency [16]. Children usually present with premature pubarche, tall stature and often accelerated bone maturation whereas adolescent females present with hyperndogene- mic symptoms such as hirsutism, acne, anovulation, menstrual dysfunction and decreased fertility. Interestingly, a significant number of individuals with NC-CAH identified in family studies are asymp- tomatic [17]. Genetic defects in the CYP21A2 gene are classified into three categories depending on the residual enzymatic activity and typically correspond to the three types of 21-OHD: salt-wasting (SW), simple virilizing (SV), and non classical (NC) CAH. In vitro studies have shown that mutations resulting in complete inactivation of 21-hydroxylase activity are associated with the SW phenotype, those that reduce 21- hydroxylase activity to approximately 2% are associated with the SV phenotype, whereas those that reduce 21-hydroxylase activity between 10% and 75% are associated with the NC-CAH phenotype. In the great Clinical Biochemistry 44 (2011) 959–963 Abbreviations: CAH, Congenital adrenal hyperplasia; NC-CAH, Non-classical adrenal hyperplasia; 17-OHP, 17-hydroxyprogesterone; 21-OHD, 21-hydroxylase; Δ4, andro- stenedione; SHBG, sex hormone binding globulin; MHC, major histocompatibility complex; ACTH, adrenocorticotropic hormone; SW, salt-wasting; SV, simple virilizing; DHEA-S, dehydroepiandrosterone sulfate; PCOS, Polycystic ovary syndrome; PP, premature pubarche; OW, overweight; IM, irregular menses; A, acne; H, hirsutism. ⁎ Corresponding author at: Paediatric Endocrine Unit, Dept. of Paediatrics, Makarios Hospital, 1474 Nicosia, Cyprus. Fax: + 357 22305072. E-mail address: nskordis@cytanet.com.cy (N. Skordis). 0009-9120/$ – see front matter © 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2011.05.013 Contents lists available at ScienceDirect Clinical Biochemistry journal homepage: www.elsevier.com/locate/clinbiochem