Purpose: Osteopathy/osteoporosis in Gaucher disease type 1 (GD1) shows variable responses to enzyme replacement therapy (ERT); the pathogenesis is incompletely understood. We aimed to investigate the effect of several gene variants on bone mineral density (BMD) and serum markers of bone metabolism in GD1.
Patients/methods: 50 adult Caucasian patients with GD1/117 controls were genotyped for gene variants in the osteoprotegerin (TNFRSF11B; OPG), estrogen receptor alpha (ESR1), calcitonin receptor (CALCR), vitamin D receptor (VDR) genes. In patients and 50 matched healthy controls, we assessed: clinical data, serum markers of bone metabolism, subclinical inflammation. BMD was measured for the first time before/during ERT (median 6.7 years).
Results: 42% of patients were splenectomized. ERT led to variable improvements in BMD. Distribution of gene variants was comparable between patients/controls. The AA genotype (c.1024+283G>A gene variant; VDR gene) was associated with lower Z scores before ERT vs. GA (P=0.033), was encountered in 82.3% of patients with osteoporosis and was more frequent in patients with pathological fractures. Z score increases during ERT were higher in patients with the CC genotype (c.9C>G variant, TNFRSF11B; OPG gene) compared to GC (P=0.003). The CC genotype (c.1340T>C variant, CALCR gene) was associated with higher Z scores before ERT than the TT genotype (P=0.041) and was absent in osteoporosis. Osteocalcin and osteoprotegerin were lower in patients vs. controls; beta crosslaps, interleukin-6, ferritin were higher.
Conclusions: We suggest for the first time a protective role against osteoporosis in GD1 patients for the CC genotype of the c.9C>G gene variant in the TNFRSFB11 (OPG) gene and for the CC genotype of the c. 1340T>C gene variant (CALCR gene), while the AA genotype of the c.1024+283G>A gene variant in the VDR gene appears as a risk factor for lower BMDs. Serum markers suggest decreased osteosynthesis, reduced inhibition of osteoclast activation, increased bone resorption and subclinical inflammation during ERT.
18 - 21 May 2019
European Society of Endocrinology