The EME1 polymorphisms were genotyped by using a matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer, and the design of primers for PCR and extension was performed using the software MassARRAY Assay Design 3.1 (Agena Bioscience, San Diego, CA). For rs3760413A>C, genomic DNA was amplified using the primers 5’-ACGTA CGAAC ACACG CACAC TTACA CACAC-3’ (forward) and 5’-ACGTA CGAAC AGATA CACAA GCCTC CACTC-3’(reverse), and the single-base extension reaction was promoted using the UEP primer 5’-GGGTT TACAC ACACA GTTTC AGCTA T-3’. For rs12450550T>C, the primers were 5’-ACGTA CGAAC CACAA TCACC AGACA CAGAG-3’ (forward) and 5’-ACGTA CGAAC AAGGG AAGGA AACGC TTCAG-3’(reverse), and the UEP primer in the single-base extension reaction was 5’- CCCTC ACCAC TCTTA CCACA C-3’. For rs11868055A>G, the primers were 5’-ACGTA CGAAC CTTAC CTCTT CACCC TACTC-3’ (forward) and 5’-ACGTA CGAAC GGTTT CACCC TAAGC AACAC-3’(reverse), and the UEP primer in the single-base extension reaction was 5’-TCTCC TCCTC AAAGT AAAAC GT-3’. The specific method has been described previously.6 (link)