• Yubing Ji, Chunyang Kang, Jiajun Chen, and Lei Zhang.
• Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China.
• Medicine (Baltimore). 2021 Jun 25; 100 (25): e26443e26443.

RationaleAutosomal dominant hypocalcaemia type 1 (ADH1) is a genetic disease characterized by benign hypocalcemia, inappropriately low parathyroid hormone levels and mostly hypercalciuria. It is caused by the activating mutations of the calcium-sensing receptor gene (CASR), which produces a left-shift in the set point for extracellular calcium.Patient ConcernsA 50-year-old man presenting with muscle spasms was admitted into the hospital. He has a positive familial history for hypocalcemia. Auxiliary examinations demonstrated hypocalcemia, hyperphosphatemia, normal parathyroid hormone level and nephrolithiasis. A missense heterozygous variant in CASR, c 613C > T (p. Arg205Cys) which has been reported in a familial hypocalciuric hypercalcemia type 1 patient was found in the patient's genotype. It is the first time that this variant is found associating with ADH1. The variant is predicted vicious by softwares and cosegregates with ADH1 in this pedigree. CASR Arg205Cys was deduced to be the genetic cause of ADH1 in the family.DiagnosisThe patient was diagnosed with ADH1 clinically and genetically.InterventionsOral calcitriol, calcium and hydrochlorothiazide were prescribed to the patient.OutcomesAfter the treatments for 1 week, the patient's symptom was improved and the re-examination revealed serum calcium in the normal range. A 3-month follow-up showed his symptom was mostly relieved.LessonsThe variant of CASR Arg205Cys, responsible for ADH1 in this family, broadened the genetic spectrum of ADH1. Further and more studies are required to evaluate the correlation between genotype and phenotype in ADH1 patients.Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.

46 keywords...

hide…