Think twice: a rare calcium sensing receptor mutation and a new diagnosis of familial hypocalciuric hypercalcaemia
Autor: | Ghusoon Abdulrasool, Louise C H Ciin, Jane J Tellam |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
Male
Sestamibi scan Hypercalcaemia Parathyroid endocrine system diseases Endocrinology Diabetes and Metabolism medicine.medical_treatment White Gastroenterology lcsh:Diseases of the endocrine glands. Clinical endocrinology Error in Diagnosis/Pitfalls and Caveats 0302 clinical medicine Palpitations DNA sequencing Vitamin D Hypocalciuria Fatigue Parathyroid adenoma education.field_of_study Parathyroid hyperplasia Calcium to creatinine clearance ratio Urinary calcium 030220 oncology & carcinogenesis Calcium-sensing receptor medicine.symptom PTH Parathyroidectomy Adult medicine.medical_specialty Population 030209 endocrinology & metabolism 03 medical and health sciences Internal medicine Internal Medicine medicine Genetics education June lcsh:RC648-665 business.industry Familial hypocalciuric hypercalcaemia Australia Neuroendocrinology medicine.disease Calcium (urine) Diet business Primary hyperparathyroidism Hypervitaminosis D Molecular genetic analysis |
Zdroj: | Endocrinology, Diabetes & Metabolism Case Reports Endocrinology, Diabetes & Metabolism Case Reports, Vol 1, Iss 1, Pp 1-5 (2020) |
ISSN: | 2052-0573 |
Popis: | Summary Distinguishing primary hyperparathyroidism (PHPT) from familial hypocalciuric hypercalcaemia (FHH) can be challenging. Currently, 24-h urinary calcium is used to differentiate between the two conditions in vitamin D replete patients, with urinary calcium creatinine clearance ratio (UCCR) 0.02 supportive of PHPT. A 26-year-old Caucasian gentleman presented with recurrent mild hypercalcaemia and inappropriately normal parathyroid hormone (PTH) following previous parathyroidectomy 3 years prior. He had symptoms of fatigue and light-headedness. He did not have any other symptoms of hypercalcaemia. His previous evaluation appeared to be consistent with PHPT as evidenced by hypercalcaemia with inappropriately normal PTH and UCCR of 0.0118 (borderline low using guidelines of >0.01 consistent with PHPT). He underwent parathyroidectomy and three parathyroid glands were removed. His calcium briefly normalised after surgery, but rose again to pre-surgery levels within 3 months. Subsequently, he presented to our centre and repeated investigations showed 24-h urinary calcium of 4.6 mmol/day and UCCR of 0.0081 which prompted assessment for FHH. His calcium-sensing receptor (CASR) gene was sequenced and a rare inactivating variant was detected. This variant was described once previously in the literature. His mother was also confirmed to have mild hypercalcaemia with hypocalciuria and, on further enquiry, had the same CASR variant. The CASR variant was classified as likely pathogenic and is consistent with the diagnosis of FHH. This case highlights the challenges in differentiating FHH from PHPT. Accurate diagnosis is vital to prevent unnecessary surgical intervention in the FHH population and is not always straightforward. Learning points: Distinguishing FHH from PHPT with co-existing vitamin D deficiency is difficult as this can mimic FHH. Therefore, ensure patients are vitamin D replete prior to performing 24-h urinary calcium collection. Individuals with borderline UCCR could have either FHH or PHPT. Consider performing CASR gene sequencing for UCCR between 0.01 and 0.02. Parathyroid imaging is not required for making the diagnosis of PHPT. It is performed when surgery is considered after confirming the diagnosis of PHPT. |
Databáze: | OpenAIRE |
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