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Markus Glaudo, Saskia Letz, Marcus Quinkler, Ulrich Bogner, Ulf Elbelt, Christian J Strasburger, Dirk Schnabel, Erwin Lankes, Sandra Scheel, Joachim Feldkamp, Christine Haag, Egbert Schulze, Karin Frank-Raue, Friedhelm Raue, Bernhard Mayr, and Christof Schöfl

Background

Homozygous inactivating mutations of the calcium-sensing receptor (CaSR) lead to neonatal severe hyperparathyroidism (NSHPT), whereas heterozygous inactivating mutations result in familial hypocalciuric hypercalcemia (FHH). It is unknown why in some cases heterozygous CaSR mutations cause neonatal hyperparathyroidism (NHPT) clinically similar to NSHPT but with only moderately elevated serum calcium.

Methods

A literature survey was conducted to identify patients with heterozygous CaSR mutations and NHPT. The common NHPT CaSR mutants R185Q and R227L were compared with 15 mutants causing only FHH in the heterozygous state. We studied in vitro calcium signaling including the functional consequences of co-expression of mutant and wild-type (wt) CaSR, patients’ phenotype, age of disease manifestation and mode of inheritance.

Results

All inactivating CaSR mutants impaired calcium signaling of wt-CaSR regardless of the patients’ clinical phenotype. The absolute intracellular calcium signaling response to physiologic extracellular calcium concentrations in vitro showed a high correlation with patients’ serum calcium concentrations in vivo, which is similar in NHPT and FHH patients with the same genotype. Pedigrees of FHH families revealed that paternal inheritance per se does not necessarily lead to NHPT but may only cause FHH.

Conclusions

There is a significant correlation between in vitro functional impairment of the CaSR at physiologic calcium concentrations and the severity of alterations in calcium homeostasis in patients. Whether a particular genotype leads to NHPT or FHH appears to depend on additional predisposing genetic or environmental factors. An individual therapeutic approach appears to be warranted for NHPT patients.

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Julia Rohayem, Lena Maria Bäumer, Michael Zitzmann, Susanne Fricke-Otto, Klaus Mohnike, Bettina Gohlke, Felix Reschke, Claus Jourdan, Hermann L Müller, Désirée Dunstheimer, Johannes Weigel, Norbert Jorch, Elke Müller-Roßberg, Erwin Lankes, Imke Gätjen, Annette Richter-Unruh, Berthold P Hauffa, Sabine Kliesch, Aniko Krumbholz, and Jurgen Bramswig

Objective: To study the impact of the quality of therapeutic control on fertility and on the prevalence of testicular adrenal rest tumors (TARTs) in young males with congenital adrenal hyperplasia (CAH).

Design: Combined cross-sectional and retrospective clinical study.

Methods: Twenty-nine patients and age-matched controls underwent clinical investigation, including semen analysis, testicular and adrenal ultrasound imaging, and serum and hair steroid analysis. The quality of therapeutic control was categorized as “poor”, “moderate” or “medium”. Evaluation of current control was based on concentrations of 17-hydroxy-progesterone and androstenedione in serum and 3 cm hair; previous control was categorized based on serum 17-hydroxy-progesterone concentrations during childhood and puberty, anthropometric and puberty data, bone age data and adrenal sizes.

Results: Semen quality was similar in males with CAH and controls (p = 0.066), however patients with “poor” past control and large TARTs, or with “poor” current CAH control, had low sperm counts. Follicle-stimulating hormone was decreased, if current CAH control was “poor” (1.8 ± 0.9 U/L; “good”: 3.9 ± 2.2 U/L); p = 0.015); luteinizing hormone was decreased if it was “poor” (1.8 ± 0.9 U/L; p = 0.041) or “moderate” (1.9 ± 0.6 U/L; “good”: 3.0 ± 1.3 U/L; p = 0.025). None of the males with “good” past CAH control, 50% of those with “moderate” past control and 80% with “poor” past control had bilateral TARTs. The prevalence of TARTs in males with severe (class null or A) CYP21A2 mutations was 53%, and 25% and 0% in those with milder class B and C mutations, respectively.

Conclusions: TART development is favoured by inadequate long-term hormonal control in CAH. Reduced semen quality may be associated with large TARTs. Gonadotropin suppression by adrenal androgen excess during the latest spermatogenic cycle may contribute to impairment of spermatogenesis.