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Objective: Our aim was to correlate 11-deoxycortisol levels obtained by two currently available techniques for 11-deoxycortisol measurement: radioimmunoassay, and high performance liquid chromatography followed by tandem mass spectrometry (MS/MS). The latter is the gold standard method for steroid hormone measurement., Materials and Methods: We selected 88 samples and the results of these two methods were compared by Deming regression., Results: The analytical sensitivity of the RIA was 0.30 ng/mL, with inadequate linearity and inadequate precision profile (34% of the samples had a CV ≥ 20%). From the selected samples, 54 had measurable levels of 11-deoxycortisol in both methods and were used in the comparison. The comparison of RIA with LC-MS/MS showed an overestimation of the results by RIA. The correlation coefficient was 0.610; linear regression slope was 3.751; and the intercept was 0.145, indicating a poor correlation between the two methods., Conclusion: We concluded that 11-deoxycortisol measured by radioimmunoassay, despite a good analytical sensitivity, showed very low specificity, precluding its use as a reliable method for 11-deoxycortisol measurement.

A loss of calcium-sensing receptor (CASR) function due to inactivating mutations can cause familial hypocalciuric hypercalcemia (FHH) or neonatal severe hyperparathyroidism (NSHPT). NSHPT represents the most severe expression of FHH and courses as a life-threatening condition. The aim of this study was to identify and characterize a CASR mutation in a female infant brought to the health service due to dehydration, apathy, lack of breast feeding and severe hypercalcemia. Molecular analysis was performed on genomic DNA of the index case and her parents. A novel homozygous mutation (p.E519X) in CASR was identified in the proband; both mother and father had the same mutation in heterozygous state, confirming their FHH condition. The mutation results in a truncated and inactive protein due to the lack of transmembrane and intracellular domains. The identification of this novel CASR gene mutation established the basis of hypercalcemia in this family and allowed a genetic counseling.