Spontaneous rib fractures in a black woman with familial hypocalciuric hypercalcemia.

[familial hypocalciuric hypercalcemia]

Familial hypocalciuric hypercalcemia (FHH ) is a rare but important consideration in the differential diagnosis of hypercalcemia . FHH results from an autosomal dominantly inherited inactivating mutation of the calcium sensing receptor (CaSR ) gene and is typically associated with a benign clinical course and normal bone mineral density .We describe the unusual case of a 57 -year old African American woman with spontaneous rib fractures who was found to have FHH due to a novel set of polymorphisms of the CaSR gene . She also had hypertension , esophageal reflux disease treated with proton pump inhibitors , osteopenia by DEXA scanning , and a prior left ankle fracture in the absence of significant trauma . There was no suggestive family history and her only sibling had a normal serum calcium . The patient was evaluated extensively for potential causes of osteoporotic fractures .I t is imperative to screen for FHH using 24 -hour urinary calcium and creatinine excretion in subjects with hypercalcemia irrespective of ethnicity and a history of non-traumatic rib fractures . This approach may prevent unnecessary neck exploration for parathyroidectomy which is unwarranted in FHH .