Atypical skeletal manifestations of rickets in a familial hypocalciuric hypercalcemia patient

A report of rickets in a teenage boy has shown that the condition can be a symptom of a genetic disorder that causes calcium imbalances. Familial hypocalciuric hypercalcemia (FHH) is caused by a mutation in the calcium-sensing receptor gene (CASR) and leads to high blood calcium levels and low urine levels. Patients are usually asymptomatic, but mice with the mutation develop skeletal problems. Here, Weibo Xia and colleagues at the Peking Union Medical College Hospital, China, describe the case of a 16-year-old boy who presented with rickets. He was subsequently diagnosed with FHH because he was found to have a previously unseen mutation in the CASR gene. The patient’s clinical profile led the authors to conclude that rickets might be a rare symptom of FHH in patients who also have a mild vitamin D deficiency.