A novel mutation in calcium-sensing receptor gene associated to hypercalcemia and hypercalciuria.

Background: Familial Hyperparathyroidism (HPT) and Familial benign Hypocalciuric Hypercalcemia (FHH) are the most common causes of hereditary hypercalcemia. FHH has been demonstrated to be caused by inactivating mutations of calcium-sensing receptor (CaSR) gene, involved in PTH regulation as well as in renal calcium excretion.Case presentation: In two individuals, father and son, we found a novel heterozygous mutation in CaSR gene. The hypercalcemia was present only in father, which, by contrast to the classic form of FHH showed hypercalciuria (from 300 to 600 mg/24 h in different evaluations) and a Calcium/Creatinine ratio of 0.031, instead of low or normal calciuria (<0.01 typical finding in FHH). His son showed the same mutation in CaSR gene, but no clinical signs or hypercalcemia although serum ionized calcium levels were close to the upper limit of normal values (1.30 mmol/L: normal range: 1.12-1.31 mmol/L). Sequence analysis revealed a point mutation at codon 972 of CaSR gene (chromosome 3q), located within cytoplasmic domain of the CaSR, that changes Threonine with Methionine. The father was treated with Cinacalcet 90 mg/day, with a decrease of total serum calcemia from an average value of 12.2 mg/dl to 10.9 mg/dl.Conclusion: This is a case of a novel inactivating point mutation of CaSR gene that determines an atypical clinical presentation of FHH, characterized by hypercalcemia, hypercalciuria and inadequate normal PTH levels. Functional assay demonstrated that the 972 M variant influenced the maturation of the protein, in terms of the post-translational glycosylation. The impairment of the receptor activity is in keeping with the specific localization of the 972 residue in the C-terminal tail, assigned to the intracellular signalling, that on the basis of the our findings appears to be differently modulated in parathyroid gland and in kidne

Simple Parameters from Complete Blood Count Predict In-Hospital Mortality in COVID-19

The clinical course of Coronavirus Disease 2019 (COVID-19) is highly heterogenous, ranging from asymptomatic to fatal forms. The identification of clinical and laboratory predictors of poor prognosis may assist clinicians in monitoring strategies and therapeutic decisions

Calcium-sensing related gene mutations in hypercalcaemic hypocalciuric patients as differential diagnosis from primary hyperparathyroidism: detection of two novel inactivating mutations in an Italian population.

Background Inactivating mutations of the calcium-sensing receptor (CaSR), of the G-protein subunit \u3b111 (GNA11) and of the adaptor-related protein complex 2, sigma 1 subunit (AP2S1) genes are responsible for familial hypocalciuric hypercalcaemia (FHH). The aim of this study was to analyse prevalence and pathogenicity of CaSR, GNA11 and AP2S1 mutations in patients with an FHH phenotype and to compare them with a sample of patients with primary hyperparathyroidism (PHPT) in order to identify the most useful laboratory parameter for a differential diagnosis. Methods Patients with an FHH phenotype were studied with polymerase chain reaction amplification and direct sequencing of the entire CaSR, GNA11 and AP2S1 coding sequences. Novel mutations were introduced in a Myc-tagged human wild-type (WT) CaSR cDNA-expressing vector, and functional assay was performed on human embryonic kidney cells evaluating expression and function of mutated proteins. Results Among 16 FHH patients, none had an inactivating GNA11 or AP2S1 mutation while 3 (18.8%) carried a CaSR mutation and 10 (62.5%) at least one CaSR polymorphism. Within the latter group, 7 of 10 patients had more than one polymorphism (4.1 \ub1 2.1 per patient). Two novel CaSR mutations [c.2120A>T (E707V) and c.2320G>A (G774S)] were identified: the E707V mutation prevented CaSR expression (western blot), whereas the G774S mutation determined a reduced receptor sensitivity to calcium (IP3 assay). PHPT patients showed significantly (P < 0.001) higher serum calcium, parathyroid hormone, urinary calcium and calcium\u2013creatinine clearance ratio (CCCR) and significantly lower serum phosphate than FHH ones. Conclusions FHH should be clearly differentiated by PHPT to avoid unnecessary surgery: CCCR could be a useful screening tool while genetic analysis should include the two novel CaSR mutations herein described. The role of multiple polymorphisms deserves further investigation in patients with an FHH phenotype

EZH2 and ZFX oncogenes in malignant behaviour of parathyroid neoplasms

Several studies reported somatic mutations of many genes (MEN1, CTNNB1, CDKIs and others) in parathyroid adenoma, although with different prevalence. Recently, activating mutations of the EZH2 and ZFX oncogenes were identified in benign parathyroid adenoma by whole exome sequencing. The same mutations had been found in blood and ovary malignant tumours. On one hand, this result raised the hypothesis that these oncogenes may play a role in the onset of parathyroid tumour, but it would also suggest they may be involved in malignant, rather benign, parathyroid neoplasm. Our aim was to verify the occurrence of selected mutations of the EZH2 and ZFX genes in an Italian cohort of 23 sporadic parathyroid carcinomas, 12 atypical and 45 typical adenomas. DNA was extracted from paraffin-embedded tissues, PCR amplified and directly sequenced. No mutations were detected in the coding sequence and boundaries of both genes in any of the samples. Two polymorphisms of the EZH2 gene were identified with different prevalence: the rs2072407 variant was present in the 30 % of the samples, in keeping with the overall frequency in larger populations, while the rs78589034 variant, located close to the 5\u2032 end of the exon 16, was detected in only one proband with familial isolated hyperparathyroidism; we investigated the possible outcome on the splicing process. EZH2 and ZFX genes do not seem to have an impact on the onset of most parathyroid tumours, both benign and malignant, though further studies on larger cohorts of different ethnicity are needed

Spectrum of PTCH mutations in Italian nevoid basal cell-carcinoma syndrome patients: identification of eleven novel alleles

The nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant genetic disease characterized by numerous basal cell carcinomas, odontogenic keratocysts of the jaws, palmar and plantal pits, skeletal abnormalities, and calcification of the falx cerebri. The gene responsible for this syndrome is the PTCH tumor suppressor gene encoding for the sonic hedgehog receptor. In this paper, we report thirteen novel mutations identified in the first screening of NBCCS patients in Italy. Except for p.T230P and p.F505_L506delinsLR, all the other mutations are predicted to determine a premature truncation of the protein

Spectrum of PTCH mutations in Italian nevoid basal cell-carcinoma syndrome patients: identification of eleven novel alleles

The nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant genetic disease characterized by numerous basal cell carcinomas, odontogenic keratocysts of the jaws, palmar and plantal pits, skeletal abnormalities, and calcification of the falx cerebri. The gene responsible for this syndrome is the PTCH tumor suppressor gene encoding for the sonic hedgehog receptor. In this paper, we report thirteen novel mutations identified in the first screening of NBCCS patients in Italy. Except for p.T230P and p.F505_L506delinsLR, all the other mutations are predicted to determine a premature truncation of the protein