A Population-Based Study of Patients With Small Cell Carcinoma of the Ovary, Hypercalcemic Type, Encompassing a 30-Year Period.

CONTEXT.­: Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare and lethal tumor, characterized by hypercalcemia and early onset and associated with germline and somatic SMARCA4 variants. OBJECTIVE.­: To identify all known cases of SCCOHT in the Slovenian population from 1991 to 2021 and present genetic testing results, histopathologic findings, and clinical data for these patients. We also estimate the incidence of SCCOHT. DESIGN.­: We conducted a retrospective analysis of hospital medical records and data from the Slovenian Cancer Registry in order to identify cases of SCCOHT and obtain relevant clinical data. Histopathologic review of tumor samples with assessment of immunohistochemical staining for SMARCA4/BRG1 was undertaken to confirm the diagnosis of SCCOHT. Germline and somatic genetic analyses were performed using targeted next-generation sequencing. RESULTS.­: Between 1991 and 2021, we identified 7 cases of SCCOHT in a population of 2 million. Genetic causes were determined in all cases. Two novel germline loss-of-function variants in SMARCA4 LRG_878t1:c.1423_1429delTACCTCA p.(Tyr475Ilefs*24) and LRG_878t1:c.3216-1G>T were identified. At diagnosis, patients were ages 21 to 41 and had International Federation of Gynecology and Obstetrics, or FIGO, stage IA-III disease. Outcomes were poor, with 6 of 7 patients dying of disease-related complications within 27 months from diagnosis. One patient had stable disease for 12 months while receiving immunotherapy. CONCLUSIONS.­: We present genetic, histopathologic, and clinical characteristics for all cases of SCCOHT identified in the Slovenian population during a 30-year period. We report 2 novel germline SMARCA4 variants, possibly associated with high penetrance. We estimate the minimal incidence of SCCOHT to be 0.12 per 1 million per year.

Suspected primary bone marrow T-cell lymphoid neoplasia causing paraneoplastic hypercalcemia in 11 dogs (2014-2021).

OBJECTIVE: To describe the clinical findings and outcome in hypercalcemic dogs that were diagnosed with T-cell lymphoid neoplasia by bone marrow evaluation. ANIMALS: 11 client-owned dogs, identified retrospectively through 2 diagnostic laboratories between 2014 and 2021. CLINICAL PRESENTATION: Cases presented with hypercalcemia and lacked overt evidence of lymphoid neoplasia in the blood or nonmedullary tissues. T-cell lymphoid neoplasia was diagnosed once the bone marrow was investigated, using a variable combination of cytology, histology, and flow cytometry. RESULTS: The median age at presentation was 5.7 years (range, 4.0 to 8.6 years). All cases were large-breed dogs, and 4 of 11 cases were Golden Retrievers. Dogs presented most commonly for polyuria and polydipsia (72%). Eight cases had neutropenia, and 10 of 11 dogs had reported thrombocytopenia. In all cases, flow cytometry identified an expansion of neoplastic small- to intermediate-sized T cells in the bone marrow that expressed low-class-II major histocompatibility complex. Neoplastic T cells in 10 of 11 cases expressed CD4. Treatments ranged from prednisone alone to multiagent chemotherapy. The median overall survival time was 260 days (range, 25 to 792 days). CLINICAL RELEVANCE: T-cell lymphoid neoplasia diagnosed via bone marrow evaluation that may represent a unique bone marrow T-cell neoplastic entity should be considered in hypercalcemic dogs with isolated cytopenias that lack peripheral lymphocytosis, lymphadenopathy, and organomegaly. Clinical outcome in these cases was variable, which may be related to nonstandardized treatments, but a subset of patients had prolonged survival.

Association between total hypercalcaemia and iliosacral lymph node metastasis in dogs diagnosed with anal sac adenocarcinoma using abdominal ultrasonography.

BACKGROUND: Anal sac adenocarcinoma (ASACA) in dogs is a malignant perianal tumour that often metastasizes to the iliosacral lymph nodes. Additionally, this tumour can be associated with hypercalcemia of malignancy. To date, no study has looked at the association between increased blood calcium levels and suspected or confirmed lymph node metastasis as a primary objective. OBJECTIVE: The objective of this study was to determine if increased total serum calcium level is associated with iliosacral lymph node metastasis in dogs diagnosed with ASACA. METHODS: Medical records of a single referral hospital were searched to identify dogs examined between 2011 and 2021 that had a diagnosis of ASACA via cytology or histopathology. Only dogs that had serum total calcium recorded and abdominal ultrasound were included in the study. All images were reviewed by a board-certified radiologist blinded to any patient identifiers. RESULTS: Of the 58 dogs, 33% (19/58) had total hypercalcaemia, and of these, 68% had confirmed or suspected iliosacral lymph node metastasis. Total hypercalcaemia was significantly associated with confirmed or suspected iliosacral lymph node metastasis (p < 0.01). However, 46% (11/24) of dogs with confirmed or suspected iliosacral lymph node metastasis were normocalcaemic. CONCLUSIONS: Based on these results, it is suggested that while the presence of total hypercalcaemia may increase the likelihood of concurrent lymph node metastasis, total hypercalcaemia alone cannot be used as a screening tool for lymph node metastasis. Dogs diagnosed with ASACA should undergo full staging regardless of total serum calcium values.

A dramatic response to checkpoint inhibitor in a woman with small cell carcinoma of the hypercalcemic type of the ovary.

OBJECTIVE: We present the rare case of a 21 year old woman with small cell carcinoma of the right ovary of the hypercalcemic type with dramatic response to checkpoint inhibitor. METHODS: Case report. RESULTS AND CONCLUSIONS: Our patient, a 22-year old woman with small cell carcinoma of the hypercalcemic type with hepatic metastases, is currently 43 months under treatment with pembrolizumab. Last MRI revealed no viable liver metastases nor other signs of recurrence. This is the longest survival of a patient with small cell carcinoma of the ovary under therapy with checkpoint inhibitors reported in the literature so far. With this report we emphasize the importance of immunohistological testing for PD-L 1. Treating clinicians should keep off-label use of immune checkpoint blockade in mind when treating this highly aggressive tumor if all other treatment options fail.

Role of hospital and patient factors in the outcome of reoperations for primary hyperparathyroidism: a retrospective multicenter cohort study.

BACKGROUND: There are few data on outcomes after reintervention for persistent or recurrent primary hyperparathyroidism (PHPT). The authors hypothesized that the variation in outcomes at the hospital level after reoperation would be significant. After accounting for this variability, some patient-level clinical criteria could be identified to help inform treatment decisions in this patient population. The aim of this study was to determine whether there is significant variation in outcomes after reoperation for PHPT between hospitals (hospital-level analysis) and identify clinical factors (patient-level analysis) that influence postoperative outcomes. MATERIALS AND METHODS: This retrospective multicenter cohort study was performed using the Eurocrine registry. Data from 11 countries and 76 hospitals from January 2015 to October 2020 were extracted. A generalized linear mixed model was used to assess the variation in outcomes at the hospital level and to identify risk factors of postoperative outcomes at the patient level. The primary endpoint (textbook outcome) was achieved when all six of the following postoperative conditions were met: no hypocalcemia or persistent hypercalcemia, no laryngeal nerve injury, no negative exploration, no normal parathyroid gland only on histopathology, and no postoperative death. RESULTS: Among 13 593 patients who underwent parathyroidectomy for PHPT, 617 (4.5%) underwent reoperative parathyroidectomy. At follow-up, 231 patients (37.4%) were hypocalcemic, 346 (56.1%) were normocalcemic without treatment, and 40 (6.5%) had persistent hypercalcemia. Textbook outcomes were achieved in 321 (52.0%) patients. The hospital-level variation in textbook outcome rates was significant ( P <0.001), and this variation could explain 29.1% of the observed outcomes. The criterion that remained significant after controlling for inter-hospital variation was 'a single lesion on sestamibi scan or positron emission tomography (PET) imaging' (odds ratio 2.08, 95% confidence interval 1.24-3.48; P =0.005). CONCLUSION: Outcomes after reoperation are significantly associated with hospital-related factors. A 'single lesion observed on preoperative sestamibi scan or PET' appears relevant to select patients before reoperation.

Prevalence and Clinicopathologic Characteristics of Hypercalcemia in Patients With Cholangiocarcinoma.

This cohort study investigates clinicopathologic and prognostic associations of hypercalcemia in patients with intrahepatic or extrahepatic cholangiocarcinoma.

Case Report: Life-threatening hypercalcemia associated with MMR-deficient endometrial carcinoma secreting parathyroid hormone.

Ectopic secretion of parathyroid hormone (PTH) is a rare cause of hypercalcemia in malignancy patients. A 56-year-old woman with life-threatening hypercalcemia was caused by poorly-differentiated endometrial carcinoma secreting PTH with concomitant nodular goiter mimic parathyroid tumors. The elevated level of PTH and calcium decreased immediately after cytoreductive surgery (CRS). The pathology confirmed mismatch repair (MMR)-deficient endometrial carcinoma with PTH expression. The patient received four-course chemotherapy and one-course immunotherapy after CRS. The disease progression led to multiple organ failure and death about five months after CRS. To our knowledge, this is the first case of hypercalcemia caused by MMR-deficient endometrial carcinoma with ectopic PTH secreting and the first report of malignancy associated hypercalcemia complicated with nodular goiter.

Small Cell Carcinoma of Ovary, Hypercalcemic Type: A Rare Case Report.

BACKGROUND: Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), is a rare neoplasm that occurs mostly in women younger than 40 years of age. The unknown histogenesis makes the diagnosis of SCCOHT difficult. SCCOHT was recently shown to be associated with SMARCA4 gene mutation. Serum calcium levels can be used as a marker of treatment response and relapse in SCCOHT. CASE REPORT: Here we report on a 16-year-old girl who presented with pelvic mass and hypercalcemia. SCCOHT was diagnosed histopathologically. However, loss of neither BRG1 nor INI1 expression was detected. SUMMARY AND CONCLUSION: The diagnosis of SCCOHT should be among the differential diagnoses in adolescents presenting with pelvic mass and hypercalcemia. We would like to share our experience with this rare case, discuss recent management, and emphasize the importance of a multidisciplinary approach. Although it is known that almost all cases have a loss of BRG1 expression and a small group exhibit loss of INI1, our patient indicates that there could be exceptional cases with hitherto undescribed genetic abnormalities.

Scrotal calcinosis in a patient treated with isotretinoin: a rare entity.

Scrotal calcinosis is a rare disorder characterized by multiple papules or nodules of calcification in the scrotal skin. The pathogenesis of this disease is poorly understood. The condition presents as several brown to yellowish asymptomatic nodules on the scrotum. Excision followed by scrotal reconstruction is the treatment of choice. It leaves a good cosmetic result with low chances of recurrence. Newer treatments, such as ablative lasers, have been proposed with very good results. We describe the case of a 28-year-old patient with a history of severe acne treated with oral isotretinoin that presented for scrotal nodules. On laboratory examination, hypercalcemia was found with normal phosphorus, parathyroid hormone, and vitamin D hormone levels. Hypercalcemia was linked to his isotretinoin therapy. Serum calcium concentrations normalized after cessation of isotretinoin and hydration. Because the patient refused surgery, a biopsy of the lesion confirmed the diagnosis of scrotal calcinosis. Then the patient was referred to a cosmetic laser center to treat his condition.

Spontaneous Remission After a Hypercalcemic Crisis Caused by an Intracystic Hemorrhage of Bilateral Parathyroid Adenomas: A Case Report and Literature Review.

Background: Hyperparathyroidism is a common cause of hypercalcemia; however, spontaneous remission after a hypercalcemic crisis caused by an intracystic hemorrhage of parathyroid adenomas is very rare. The question, then, is "What is the best treatment strategy for this type of case?" Method: A 47-year-old male patient with primary hyperparathyroidism and a hypercalcemic crisis is reported. Hypercalcemia was spontaneously relieved thereafter. Postoperative paraffin pathology results indicated an intracystic hemorrhage of bilateral parathyroid adenomas. Results: After the case report, a literature review is also included to summarize the clinical features of this patient and to provide special reference for clinical diagnosis and treatment of similar cases. Conclusions: The choice of surgical timing for such cases can be made based on the comprehensive consideration of clinical symptoms and changes in parathyroid function.

Changes in Serum Calcium and Treatment of Hypoparathyroidism During Pregnancy and Lactation: A Single-center Case Series.

BACKGROUND: Hypoparathyroidism (hypo-PT) is rare, and studies on hypo-PT, especially during pregnancy and lactation, are limited. DESIGN AND SETTING: This was a retrospective study on a relatively large case series in a single center from mainland China. METHODS: A total of 19 patients with 25 pregnancies, diagnosed with hypo-PT before pregnancy, were enrolled. Data on clinical characteristics and treatment strategies at onset time and around pregnancy period were collected. RESULTS: During pregnancy, except for 2 patients with missing data, 5 patients with 6 pregnancies (6/23, 26.1%) experienced improved hypo-PT condition, defined as an increased serum calcium level; 4 patients with 4 pregnancies (4/23, 17.4%) experienced worsened hypo-PT condition, defined as a more than 0.2 mmol/L decline in the serum calcium level; and 3 patients with 3 pregnancies (3/23, 13.0%) remained in stable hypo-PT condition. The prevalence of adverse pregnancy outcomes was 30.4% (4/23 for preterm delivery; 3/23 for miscarriage). The serum calcium and 24-hour urine calcium levels significantly increased during lactation compared with pregnancy (2.57 ± 0.34 vs 1.99 ± 0.11 mmol/L, P < 0.001; 12.28 ± 5.41 vs 8.63 ± 3.22 mmol/L, P = 0.013), and 5 patients with 5 lactations (5/12, 41.7%) developed hypercalcemia in the first 2 months after delivery. CONCLUSIONS: Female patients with hypo-PT had different changes in calcium homeostasis and a high prevalence of adverse outcomes during pregnancy. Thus, they should be monitored closely to maintain the optimal serum calcium level. Decreasing drug dosage during the lactation period should be considered to avoid hypercalcemia.

Systems-Level Opportunities in the Management of Primary Hyperparathyroidism: An Informatics-based Assessment.

CONTEXT: Primary hyperparathyroidism (PHPT), a leading cause of hypercalcemia and secondary osteoporosis, is underdiagnosed. OBJECTIVE: This work aims to establish a foundation for an electronic medical record-based intervention that would prompt serum parathyroid hormone (PTH) assessment in patients with persistent hypercalcemia and identify care gaps in their management. METHODS: A retrospective cohort study was conducted in a tertiary academic health system of outpatients with persistent hypercalcemia, who were categorized as having classic or normohormonal PHPT. Main outcome measures included the frequencies of serum PTH measurement in patients with persistent hypercalcemia, and their subsequent workup with bone mineral density (BMD) assessment, and ultimately, medical therapy or parathyroidectomy. RESULTS: Among 3151 patients with persistent hypercalcemia, 1526 (48%) had PTH measured, of whom 1377 (90%) were confirmed to have classic (49%) or normohormonal (41%) PHPT. PTH was measured in 65% of hypercalcemic patients with osteopenia or osteoporosis (P < .001). At median 2-year follow-up, bone density was assessed in 275 (20%) patients with either variant of PHPT (P = .003). Of women aged 50 years or older with classic PHPT, 95 (19%) underwent BMD assessment. Of patients with classic or normohormonal PHPT, 919 patients (67%) met consensus criteria for surgical intervention, though only 143 (15%) underwent parathyroidectomy. CONCLUSION: Within a large academic health system, more than half of patients with confirmed hypercalcemia were not assessed for PHPT, including many patients with preexisting bone disease. Care gaps in BMD assessment and medical or surgical therapy represent missed opportunities to avoid skeletal and other complications of PHPT.

Efficacy and Safety of Intravenous Pamidronate for Parathyroid Hormone-dependent Hypercalcemia in Hospitalized Patients.

CONTEXT: Bisphosphonates are effective for hypercalcemia of malignancy (HOM). Efficacy and safety data for bisphosphonates in parathyroid hormone-related hypercalcemia (PTHRH) are rare, including pamidronate (Pam), which is not indicated for this condition. OBJECTIVE: This work aims to evaluate the efficacy and safety of Pam for moderate-to-severe PTHRH. METHODS: This retrospective case-control study was conducted at a tertiary care medical center. Patients included adults hospitalized with serum calcium levels greater than 12 mg/dL, from October 29, 2013 to December 17, 2019. Etiology was categorized as PTHRH or PTH-independent. Clinical and laboratory data of PTHRH patients treated with Pam (PTHRH-Pam+) were compared to Pam-untreated counterparts (PTHRH-Pam-). RESULTS: Thirty-four patients with 37 hospitalizations for PTHRH (Pam-treated and -untreated) met the inclusion criteria. Pam was given in 24 of 37 cases (64.8%). Admission serum calcium levels for the PTHRH-Pam+ group were higher than for PTHRH-Pam- group (14.4 mg/dL vs 13.0 mg/dL, P = .005). Median total Pam dose was 60 mg (range, 30-180 mg) in the treated group. Serum calcium decreased 3.5 mg/dL for PTHRH-Pam+ vs 1.6 mg/dL for PTHRH-Pam- (P = .003). No PTHRH-Pam+ patients developed hypocalcemia or acute kidney injury. Nadir serum phosphorus levels were lower in the PTHRH-Pam+ vs PTHRH-Pam- group (1.7 mg/dL vs 2.4 mg/dL, respectively, P = .004). Three PTHRH-Pam+ patients developed severe hypophosphatemia; all resolved with intravenous and oral supplementation. Seventeen patients underwent parathyroidectomy, of whom 10 received Pam within 28 days preoperatively. Postoperatively, 4 developed hypocalcemia and 3 hypophosphatemia. CONCLUSION: This study demonstrates that Pam is effective and safe for treating PTHRH, while ensuring close laboratory monitoring of calcium and phosphorus metabolism. Larger, prospective studies are needed to establish the role of Pam and other potent bisphosphonates in moderate-to-severe PTHRH.

Severe hypercalcemia in an infant with unbalanced translocation of chromosomes 2 and 8: a possible contribution of 2p duplication.

OBJECTIVES: We report an uncommon case of severe hypercalcemia in an infant with unbalanced translocation of chromosomes 2 and 8 with 2p duplication. After ruling out all the possible etiologies of hypercalcemia, we speculated a potential contribution of 2p duplication involving 225 genes. CASE PRESENTATION: An 11-month old female infant with global developmental delay, failure to thrive (FTT), hypotonia, amblyopia, constipation, and recent onset emesis was admitted to the hospital after an incidental diagnosis of severe hypercalcemia. Labs revealed normal serum phosphate, serum 25 (OH) vitamin D levels, and low serum parathyroid hormone (PTH) level. Elevated urinary calcium to creatinine ratio ruled out the possibility of hypocalciuric hypercalcemia. Endocrinological evaluations, including thyroid function test, Adrenocorticotropic hormone (ACTH), Cortisol, Insulin like growth factor 1 (IGF-1) were all normal. Transient elevation of parathyroid hormone related peptide (PTHrP) level was noted, but skeletal survey, chest X-ray and lab values including low 1,25 (OH)2 cholecalciferol, lactate dehydrogenase (LDH), uric acid (UA), erythrocyte sedimentation rate (ESR) excluded granulomatous diseases and malignancies. Further evaluation with chromosomal microarray (CMA) and whole exome gene sequencing (WES) showed an unbalanced chromosomal translocation with 2p duplication involving 225 genes. The infant showed an improvement with medical management. CONCLUSIONS: 2p duplication syndrome is a rare syndrome characterized by developmental delay, feeding problems, FTT, hypotonia, constipation, and unusual facial features as noted in our case. However, hypercalcemia has been only reported once earlier in 2p duplication syndrome, which was the presenting feature of our case. We attributed this genetic syndrome as an underlying etiology for hypercalcemia after ruling out all the common potential causes of hypercalcemia.

Ap2s1 mutation causes hypercalcaemia in mice and impairs interaction between calcium-sensing receptor and adaptor protein-2.

Adaptor protein 2 (AP2), a heterotetrameric complex comprising AP2α, AP2ß2, AP2µ2 and AP2σ2 subunits, is ubiquitously expressed and involved in endocytosis and trafficking of membrane proteins, such as the calcium-sensing receptor (CaSR), a G-protein coupled receptor that signals via Gα11. Mutations of CaSR, Gα11 and AP2σ2, encoded by AP2S1, cause familial hypocalciuric hypercalcaemia types 1-3 (FHH1-3), respectively. FHH3 patients have heterozygous AP2S1 missense Arg15 mutations (p.Arg15Cys, p.Arg15His or p.Arg15Leu) with hypercalcaemia, which may be marked and symptomatic, and occasional hypophosphataemia and osteomalacia. To further characterize the phenotypic spectrum and calcitropic pathophysiology of FHH3, we used CRISPR/Cas9 genome editing to generate mice harboring the AP2S1 p.Arg15Leu mutation, which causes the most severe FHH3 phenotype. Heterozygous (Ap2s1+/L15) mice were viable, and had marked hypercalcaemia, hypermagnesaemia, hypophosphataemia, and increases in alkaline phosphatase activity and fibroblast growth factor-23. Plasma 1,25-dihydroxyvitamin D was normal, and no alterations in bone mineral density or bone turnover were noted. Homozygous (Ap2s1L15/L15) mice invariably died perinatally. Co-immunoprecipitation studies showed that the AP2S1 p.Arg15Leu mutation impaired protein-protein interactions between AP2σ2 and the other AP2 subunits, and also with the CaSR. Cinacalcet, a CaSR positive allosteric modulator, decreased plasma calcium and parathyroid hormone concentrations in Ap2s1+/L15 mice, but had no effect on the diminished AP2σ2-CaSR interaction in vitro. Thus, our studies have established a mouse model that is representative for FHH3 in humans, and demonstrated that the AP2S1 p.Arg15Leu mutation causes a predominantly calcitropic phenotype, which can be ameliorated by treatment with cinacalcet.

Severe hypercalcemia caused by parathyroid hormone in a rectal cancer metastasis: a case report.

BACKGROUND: Hypercalcemia of malignancy is relatively common in several cancers. However, in colorectal cancer, paraneoplastic phenomena that cause hypercalcemia is uncommon. In the few cases that are reported, secretion of parathyroid hormone-related peptide mediates the effect. We describe the first case of severe hypercalcemia mediated by intact parathyroid hormone secretion from a bone metastasis of colorectal origin. This was a diagnostic and therapeutic challenge. CASE PRESENTATION: A 68-year-old male treated for rectal adenocarcinoma 10 years earlier developed a bone metastasis. After initial treatment of the metastasis with surgery and irradiation, he developed a relapse with severe hypercalcemia and corresponding elevated parathyroid hormone levels. The workup showed no signs of parathyroid adenomas, but the metastasis produced intact parathyroid hormone. The hypercalcemia was successfully treated by irradiation and osteoclast inhibitor, and the patient received chemotherapy. Survival was 24 months from the onset of hypercalcemia. CONCLUSIONS: Proper diagnosis of the uncommon endocrine disturbance allowed targeted therapy and avoidance of neck exploration for wrongly suspecting primary hyperparathyroidism. Intact parathyroid hormone should be measured in cases of malignant hypercalcemia.

Analysis of vitamin D3 metabolites in survivors of infantile idiopathic hypercalcemia caused by CYP24A1 mutation or SLC34A1 mutation.

Infantile hypercalcemia (IH), is a rare disorder caused by CYP24A1 or SLC34A1 variants which lead to disturbed catabolism of 25(OH)D3 and 125(OH)2D3 or increased generation of 125(OH)2D3. AIM OF STUDY: To assess the status of 2425(OH)2D3 and other markers of vitamin D in IH survivors, in whom variants of CYP24A1 or SLC34A1 gene were found and to compare these unique biochemical features with those obtained from subjects who were diagnosed in the first year of life with hypercalcemia, elevated 25(OH)D3 and low PTH but in whom neither CYP24A1 nor SLC34A1 variant was found. PATIENTS AND METHODS: 16 IH survivors in whom CYP24A1 (n = 13) or SLC34A1 (n = 3) variants were found and 41 subjects in whom hypercalcemia was diagnosed in the first year of life but in whom CYP24A1 or SLC34A1 variants were not found were included in the study. 25(OH)D3, 3-epi-25(OH)D3, 25(OH)D2, 2425(OH)2D3 were assessed by liquid chromatography coupled with tandem mass spectrometry. 125(OH)2D3 concentrations were assessed by chemiluminescence. RESULTS: Subjects with CYP24A1 variants, despite normal 25(OH)D3 levels, had higher 25(OH)D3/2425(OH)2D3 ratio values (487; 265-1073 ng/mL) when compared to subjects with SLC34A1 variants (16; 16-23 ng/mL) and with subjects in whom CYP24A1 or SLC34A1 were not found (56; 9-56 ng/mL) (p = 0.00003). Separation of interfering metabolite further increased differences between subjects with and without CYP24A1 mutation. CONCLUSIONS: Survivors of IH with CYP24A1 variant, despite being normocalcemic, still presented extremely high 25(OH)D3/2425(OH)2D3 ratio values. Separation of interfering compound further increased differences between subjects with CYP24A1 mutation and without this mutation.

The Calcium-Sensing Receptor Is Essential for Calcium and Bicarbonate Sensitivity in Human Spermatozoa.

CONTEXT: The calcium-sensing receptor (CaSR) is essential to maintain a stable calcium concentration in serum. Spermatozoa are exposed to immense changes in concentrations of CaSR ligands such as calcium, magnesium, and spermine during epididymal maturation, in the ejaculate, and in the female reproductive environment. However, the role of CaSR in human spermatozoa is unknown. OBJECTIVE: This work aimed to investigate the role of CaSR in human spermatozoa. METHODS: We identified CaSR in human spermatozoa and characterized the response to CaSR agonists on intracellular calcium, acrosome reaction, and 3',5'-cyclic adenosine 5'-monophosphate (cAMP) in spermatozoa from men with either loss-of-function or gain-of-function mutations in CASR and healthy donors. RESULTS: CaSR is expressed in human spermatozoa and is essential for sensing extracellular free ionized calcium (Ca2+) and Mg2+. Activators of CaSR augmented the effect of sperm-activating signals such as the response to HCO3- and the acrosome reaction, whereas spermatozoa from men with a loss-of-function mutation in CASR had a diminished response to HCO3-, lower progesterone-mediated calcium influx, and were less likely to undergo the acrosome reaction in response to progesterone or Ca2+. CaSR activation increased cAMP through soluble adenylyl cyclase (sAC) activity and increased calcium influx through CatSper. Moreover, external Ca2+ or Mg2+ was indispensable for HCO3- activation of sAC. Two male patients with a CASR loss-of-function mutation in exon 3 presented with normal sperm counts and motility, whereas a patient with a loss-of-function mutation in exon 7 had low sperm count, motility, and morphology. CONCLUSION: CaSR is important for the sensing of Ca2+, Mg2+, and HCO3- in spermatozoa, and loss-of-function may impair male sperm function.