scholarly journals A Novel Mutation of the Calcium-Sensing Receptor Gene Causing Familial Hypocalciuric Hypercalcemia Complicates Medical Followup after Roux-en-Y Gastric Bypass: A Case Report and a Summary of Mutations Found in the Same Hospital Laboratory

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Elin Rebecka Carlsson ◽  
Mai-Britt Toft Nielsen ◽  
Anne Mette Høgh ◽  
Rikke Veggerby Grønlund ◽  
Mogens Fenger ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Novel Mutation ◽  
Calcium Supplementation ◽  
Receptor Gene ◽  
Familial Hypocalciuric Hypercalcemia ◽  
Calcium Sensing Receptor ◽  
Clearance Ratio ◽  
Casr Gene ◽  
Calcium Sensing ◽  
Increased Risk

Heterozygous inactivating mutations in the calcium-sensing receptor (CaSR) gene are known to cause familial hypocalciuric hypercalcemia (FHH), usually a benign form of hypercalcemia without symptoms of a disrupted calcium homeostasis. FHH can be mistaken for the more common primary hyperparathyroidism (PHPT), for which surgical treatment may be needed. We describe a case of a 36-year-old woman with hypercalcemia and elevated PTH, initially suspected of having PHPT. Sequencing of the CaSR-gene revealed a mutation in nucleotide 437, changing the amino acid in position 146 from Glycine to Aspartate. The mutation was previously undescribed in the literature, but a very low calcium:creatinine clearance ratio supported the diagnosis FHH. A few years later, the patient’s two daughters were tested and the association between mutation and hypercalcemia could be confirmed. The patient was gastric bypass-operated and therefore, due to malabsorption and increased risk of fracture, was in need of adequate calcium supplementation. The chronically elevated calcium levels challenged medical followup, as calcium sufficiency could not be monitored in a traditional manner. Eventually the patient developed elevated alkaline phosphatase, a further increased PTH and a decreased DXA T-score indicating calcium deficiency and bone resorption. As a supplement, all CaSR-mutations found at our hospital, 2005-2018.

scholarly journals Atypical Presentation of Familial Hypocalciuric Hypercalcemia: Case Report

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A182-A183
Author(s):  
Dalal S Ali ◽  
Karel Dandurand ◽  
Aliya Aziz Khan
Keyword(s):  
Vitamin D ◽  
Primary Hyperparathyroidism ◽  
Dna Analysis ◽  
Receptor Gene ◽  
Familial Hypocalciuric Hypercalcemia ◽  
Calcium Sensing Receptor ◽  
Clearance Ratio ◽  
Subtotal Parathyroidectomy ◽  
Casr Gene ◽  
Calcium Sensing

Abstract Background: Differentiation between familial hypocalciuric hypercalcemia (FHH) and primary hyperparathyroidism (PHPT) can be challenging in certain cases in the absence of DNA analysis of the calcium sensing receptor gene. The distinction between those two clinical entities with overlapping biochemical features therefore relies on the calcium to creatinine clearance ratio (CCCR), which is expected to be low in FHH (<0.01 in 80% of cases and between 0.01 and 0.02 in approximately 20% of patients)1. Patients with PHPT usually have a CCCR of>= 0.02. A lower CCCR between 0.01 and 0.02 can be seen in approximately 20% of patients1,2and is more commonly seen in the presence of vitamin D insufficiency, impaired renal function, low calcium intake or being of African descent. It is advised to stop drugs which can contribute to hypercalcemia and lower the CCCR such as thiazide diuretics prior to evaluating the CCCR. Clinical Case: A 56-year-old lady was referred for evaluation of persistent hypercalcemia post parathyroidectomy and fatigue. She had mildly elevated ionized serum calcium (iCa) and a mid-normal PTH with a CCCR of 0.024. She had a normal BMD with no prior fragility fractures and passed a kidney stone prior to her presentation. Physical exam was unremarkable. She had previously travelled to Tampa and had a subtotal parathyroidectomy 3 glands (RU, LU, RL) for a possible diagnosis of PHPT, tissue biopsy showed hyperplastic parathyroids. Her MEN1 gene analysis was negative for MEN1 mutation and MRI of the abdomen was unremarkable. Her mother had a diagnosis of PHPT and osteoporosis. The iCa remained mildly elevated at 1.43 mmol/L (1.15–1.3) with a 24 hr urinary CCCR at 0.024 and a mid-normal PTH of 4.4 pmol/L (1.6–6.9). Her eGFR was 104 mls/min, 25 vitamin D 82 nmol/L (75–250), 1,25 dihydroxy vitamin D 122 pmol/L (60–206), PO4 0.90 mmol/L (0.8–1.45) and alkaline phosphatase 46 U/L (35–120) were all normal. She continued to have mild symptoms of hypercalcemia and her bone scan was negative for underlying skeletal pathology. DNA studies for mutations in the CaSR gene were completed. This confirmed the presence of a heterozygous loss of function mutation in the CASR gene at c493-2A>G which appears to be pathogenic. Conclusion: The CCCR is useful in differentiating PHPT from FHH however in certain cases of FHH the CCCR may be higher then expected and we have now confirmed the presence of FHH with a molecular diagnosis in a patient with a CCCR as high as 0.02. References: 1 Gunn, IR, Gaffney, D. Clinical and laboratory features of calcium-sensing receptor disorders: a systematic review. Ann Clin Biochem 2004; 41:441–58 2 Stephen J. Marx, Letter to the Editor: Distinguishing Typical Primary Hyperparathyroidism From Familial Hypocalciuric Hypercalcemia by Using an Index of Urinary Calcium, The Journal of Clinical Endocrinology & Metabolism, 2015

scholarly journals SAT-351 A Novel Mutation in the Calcium-Sensing Receptor Gene Presenting in a Kindred as Autosomal Dominant Familial Hypocalciuric Hypercalcemia

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Jordan Bushman ◽  
Ajaz Banka
Keyword(s):  
Genetic Analysis ◽  
Novel Mutation ◽  
Receptor Gene ◽  
Family Members ◽  
Heterozygous Mutation ◽  
Familial Hypocalciuric Hypercalcemia ◽  
Loss Of Function ◽  
Calcium Sensing Receptor ◽  
Casr Gene ◽  
Calcium Sensing

Abstract Rationale: Familial hypocalciuric hypercalcemia (FHH) is a benign cause of hypercalcemia. The majority of cases result from an inactivating mutation in the calcium-sensing receptor (CaSR). While affected patients are usually asymptomatic and require no treatment, this condition may go unrecognized and inappropriate parathyroidectomy for presumed primary hyperparathyroidism could be performed. Over 130 mutations in the CaSR gene have been reported and novel variants continue to emerge. Methods: The initial patient was a 49 year-old female who presented with mild hypercalcemia, elevated PTH and undetectable urine calcium. She reported several of her family members had elevated calcium levels. Given high clinical suspicion for FHH genetic analysis was performed. Results: Sequencing of the CaSR gene revealed a point mutation at c.1744T>A which resulted in p.Cys582Ser in exon 7. This cystine residue is highly conserved and predictive algorithms suggest this variant is likely disruptive leading to heterozygous loss of function in the CaSR. The patient’s 26 year-old daughter was tested and found to have the same mutation. Conclusion: We report the identification of a novel heterozygous mutation in the CaSR gene manifesting as FHH in a family of Iraqi decent. Additional family members are currently undergoing genetic analysis which will be included at the time of presentation.

scholarly journals A Novel Mutation in the Calcium-Sensing Receptor Gene in a Chinese Subject with Persistent Hypercalcemia and Hypocalciuria1

2001 ◽  
Vol 86 (1) ◽  
pp. 13-15
Author(s):  
Tjin-Shing Jap ◽  
Yi-Chi Wu ◽  
Shwu-Fen Jenq ◽  
Gin-Sing Won
Keyword(s):  
Novel Mutation ◽  
Receptor Gene ◽  
Intracellular Loop ◽  
Calcium Sensing Receptor ◽  
Autosomal Dominant Disorder ◽  
Casr Gene ◽  
Calcium Sensing ◽  
Additional Group ◽  
Life Threatening ◽  
Chinese Subjects

Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder characterized by high penetrance of relatively benign, lifelong persistent hypercalcemia and hypocalciuria. By contrast, neonatal severe hyperparathyroidism represents a life-threatening form of hypercalcemia that can cause the early newborn mortality if immediate intervention is not undertaken. Both disorders are due to inactivation mutation of the human calcium-sensing receptor (CaSR) gene on chromosome 3q21-24. Up to now, more than 30 mutations in the CaSR gene associated with FHH have been described. In this study, we analyzed one 79-yr-old male with hypocalciuric hypercalcemia without siblings or children to compare with an additional group of 50 normal Chinese subjects in Taiwan. DNA sequence analysis of the CaSR gene was performed. The result showed that the proband had a heterozygous nonsense mutation in exon 7 of the CaSR gene at codon 648 (CGA→TGA/Arg→Ter). This mutation, located in the COOH-terminal of the first intracellular loop of the CaSR, predicts a markedly truncated protein. We have identified a novel R648X mutation in the CaSR gene in one patient with FHH in Taiwan

Identification of a novel calcium-sensing receptor (CASR) gene mutation in a patient with familial hypocalciuric hypercalcemia

2019 ◽  
Vol 493 ◽  
pp. S229
Author(s):  
M. Ortiz Espejo ◽  
R. Batanero Maguregui ◽  
C. Montalban Carrasco ◽  
L. Ramos Ramos ◽  
R. García Sardina ◽  
...  
Keyword(s):  
Gene Mutation ◽  
Familial Hypocalciuric Hypercalcemia ◽  
Calcium Sensing Receptor ◽  
Casr Gene ◽  
Calcium Sensing
Sign in / Sign up

Export Citation Format

Share Document