Table 6. Genotype and allele frequencies of polymorphisms across selenoprotein genes by serum selenium concentration in Tibetan population.

SNPs	Controls	KBD	Controls	KBD	Trend	Higher group	Lower group	Higher group	Lower group	Trend
	number	number	Freq.	Freq.	p-value	number	number	Freq.	Freq.	p-value
GPX1(rs1050450)					0.932					0.2849
CC	147	155	0.812	0.816		174	125	0.798	0.839
CT	34	35	0.188	0.184		44	24	0.202	0.161
TT	0	0	0	0		0	0	0	0
C-allele	328	345	0.906	0.908		392	274	0.899	0.919
T-allele	34	35	0.094	0.092		44	24	0.101	0.081
P_HWE			0.1631	0.162				0.2849	0.0975
GPX1(rs1800668)					0.701					0.924
CC	182	197	0.809	0.804		173	206	0.797	0.811
CT	39	41	0.173	0.167		41	40	0.189	0.157
TT	4	7	0.018	0.029		3	8	0.014	0.031
C-allele	403	435	0.896	0.888		387	452	0.892	0.89
T-allele	47	55	0.104	0.112		47	56	0.108	0.11
P_HWE			0.2706	0.0121				0.749	0.002
GPX1(rs3811699)					0.887					0.8969
TT	201	212	0.841	0.841		185	228	0.833	0.848
CT	34	37	0.142	0.147		35	36	0.158	0.134
CC	4	3	0.017	0.012		2	5	0.009	0.019
T-allele	436	461	0.912	0.915		405	492	0.912	0.914
C-allele	42	43	0.088	0.085		39	46	0.088	0.086
P_HWE			0.082	0.347				0.018	0.8099
DIO2(rs225014)					0.19					0.6357
TT	57	94	0.425	0.337		63	88	0.389	0.351
CT	61	150	0.455	0.538		72	139	0.444	0.554
CC	16	35	0.119	0.125		27	24	0.167	0.096
T-allele	175	338	0.653	0.606		198	315	0.611	0.627
C-allele	93	220	0.347	0.394		126	502	0.389	0.373
P_HWE			0.9585	0.0359				0.0035	0.4085
TrxR2(rs5748469)					0.461					0.6092
AA	136	209	0.716	0.749		154	191	0.748	0.726
AC	49	63	0.258	0.226		47	65	0.228	0.247
CC	5	7	0.026	0.025		5	7	0.024	0.027
A-allele	321	481	0.845	0.862		355	447	0.862	0.85
C-allele	59	77	0.155	0.138		57	79	0.138	0.15
P_HWE			0.8164	0.3958				0.5367	0.606