Bone health ECHO case report: High bone mass in a patient with chronic kidney disease.

Bone Health ECHO (Extension of Community Healthcare Outcomes) is a growing family of online educational programs. Its mission is to enhance delivery of best practice skeletal healthcare worldwide. Each program typically consists of a didactic lecture and discussion of clinical cases with diagnostic and treatment dilemmas. Here we present a Bone Health ECHO case of a 39-year-old man who has received hemodialysis for 12 years. This case is characterized by the development of chronic kidney disease - mineral and bone disorder (CKD-MBD) which was managed using conservative treatment to maintain phosphate and calcium levels within the reference range in spite of severe secondary hyperparathyroidism, after the patient declined parathyroidectomy. Although this patient had multiple vertebral fractures with height loss, his bone mineral density was higher than expected for his age and gradually increased over the period of observation. Whole-exome sequencing showed a heterozygous, likely pathogenic variant in LEMD3 gene (13 exon HG38, chr12:65246271dup, с.2682dup in a heterozygous state), which may explain the high bone mass phenotype. As a result of the ECHO presentation, we decided that successful treatment of CKD-MBD would be the most effective approach to managing his bone fragility. His high bone mass phenotype was most likely associated with LEMD3 gene variant. This patient does not require any specific anti-osteoporotic treatment at this time; however, he is likely to benefit from parathyroid surgery.