Objectives
Glucocorticoids such as dexamethasone have pleiotropic effects, including desired antileukemic, anti-inflammatory or immunosuppressive effects, and undesired metabolic or toxic effects. The most serious adverse effects of dexamethasone among patients with acute lymphoblastic leukemia (ALL) are osteonecrosis and thrombosis. To identify inherited genomic variation involved in these serious adverse effects, we performed genome-wide association studies (GWAS) by analyzing 14 pleiotropic glucocorticoid phenotypes in 391 patients with ALL.
Methods
We used the Projection Onto the Most Interesting Statistical Evidence (PROMISE) integrative analysis technique to identify genetic variants associated with pleiotropic dexamethasone phenotypes, stratifying for age, sex, race, and treatment, and compared results to conventional single-phenotype GWAS. The phenotypes were: osteonecrosis, central nervous system toxicity, hyperglycemia, hypokalemia, thrombosis, dexamethasone exposure, body mass index, decreased growth trajectory, and levels of cortisol, albumin, asparaginase antibodies, and change in cholesterol, triglycerides, and low density lipoproteins after dexamethasone.
Results
The integrative analysis identified more pleiotropic SNP variants (p = 1.46 × 10−215), and these variants were more likely to be in gene regulatory regions (p = 1.22×10−6), than traditional single-phenotype GWAS. The integrative analysis yielded genomic variants (rs2243057 & rs6453253) in F2RL1, a receptor that functions in hemostasis, thrombosis, and inflammation, which were associated with pleiotropic effects, including osteonecrosis and thrombosis, and were in regulatory gene regions.
Conclusions
The integrative pleiotropic analysis identified risk variants for osteonecrosis and thrombosis not identified by single-phenotype analysis that may have importance for patients with underlying sensitivity to multiple dexamethasone adverse effects.