Endocrine Abstracts

Familial hypocalciuric hypercalcaemia (FHH) is a characteristically asymptomatic condition that is caused principally by calcium sensing receptor gene (CASR) mutations and less frequently by GNA11 or AP2S1 mutations. We report a case of recurrent symptomatic pancreatitis in an FHH patient. The 17-year-old patient was hospitalized with abdominal pain and raised pancreatic enzymes due to acute pancreatitis. The only predisposing factor on investigation was a very elevated serum calcium level (3.3 mmol/l; NR: 2.15–2.60). This was associated with concomitantly moderately elevated PTH (33 ng/l; NR: 4–26), normal 25-OH vitamin D (44 ng/ml; NR: 30–80), elevated 1,25(OH)₂ vitamin D (133 pg/ml; NR: 23–109), and undetectable urinary calcium. Family history revealed that the patient’s grandmother was also known to suffer from hypocalciuric hypercalcaemia, and that hypercalcaemia had been found in the patient’s mother, uncle, brother and sister. CASR sequencing revealed the patient (and family members) to be heterozygotic for a R185Q mutation, previously suggested to be a dominant negative mutation and leads to higher calcium levels than other known CASR mutations. Cinacalcet treatment lowered serum calcium to 2.95 mmol/l and the patient has not presented new pancreatitis episodes.