Markedly elevated bone mineral density in genetically elusive familial hypocalciuric hypercalcemia: A case report with targeted genetic analysis of eight candidate genes.

Yatsuga, Shuichi; Kozakai, Yutaka · Bone Rep · 2026

case_report · Level V

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Abstract

We report an 88-year-old Japanese woman with markedly elevated bone mineral density (lumbar spine 212% of young adult mean, Z-score + 10.0 SD) diagnosed with familial hypocalciuric hypercalcemia based on a urinary calcium-to-creatinine ratio of 0.06. Tergeted genetic testing of eight genes revealed no pathogenic variants; a <i>CASR</i> variant (c.1733-9A>G) was a common Japanese polymorphism (frequency 1/808). This genetically elusive case highlights the extreme skeletal phenotype in FHH and the essential role of population-specific databases in variant interpretation. ©The Authors. All rights reserved.