Autosomal dominant hypocalcaemia: identification of two novel variants of CASR gene

Autosomal dominant hypocalcaemia is a rare aetiology of hypocalcaemia, caused by gain-of-function mutations of the calcium-sensing receptor (CASR) gene. We present two cases of two asymptomatic women (50-year-old-case 1 and 25-year-old-case 2), referred to our endocrinology department for investigation of hypocalcaemia, hyperphosphatemia and inappropriately low parathormone. Both patients had relatives with the same laboratorial findings. At diagnosis, both patients presented basal ganglia calcifications. Genetic analysis was performed, identifying two novel heterozygous CASR variants: c.2269G>A (p.Glu757Lys) and c.2086C>G (p.Leu696Val), respectively, for case 1 and case 2. Affected individuals started oral calcium and vitamin D analogues, aiming to a low-normal calcium level. They remain under observation and are asymptomatic.