Association between 𝜺2/3/4, Promoter Polymorphism (−491A/T, −427T/C, and −219T/G) at the Apolipoprotein E Gene, and Mental Retardation in Children from an Iodine Deficiency Area, China

Table 2

Distribution of allele and genotype across ApoE 𝜀2/𝜀3/𝜀4,  −491A/T, −427T/C, and −219G/T polymorphisms in MR, borderline MR, and control.

Loci		Allele					Genotype
	𝑁^a	𝜀2	𝜀3	𝜀4	𝑃^b	𝑁^a	𝜀2+^c	𝜀4+^c	𝜀3/𝜀3	𝑃^b
𝜀2/𝜀3/𝜀4
MR	260	26 (23.4)	206 (21.4)	28 (26.9)	0.82	130	24 (23.4)	80 (20.3)	26 (28.3)	0.46
Borderline MR	248	20 (18.0)	211 (22.0)	17 (16.4)		123^a	18 (18.0)	89 (22.5)	16 (17.4)
Control	668	65 (58.6)	544 (56.6)	59 (56.7)		329^a	53 (58.6)	226 (57.2)	50 (54.3)
	𝑁^a	T	A		𝑃^b	𝑁^a	T/T	T/A	A/A	𝑃^b
−491A/T
MR	260	3 (14.3)	257 (22.2)		0.21	130	0 (0)	3 (15.8)	127 (22.4)	0.45
Borderline MR	248	3 (14.3)	245 (21.1)			124	0 (0)	3 (15.8)	121 (21.3)
Control	668	15 (71.4)	653 (56.7)			334	1 (100)	13 (68.4)	320 (56.3)
	𝑁^a	C	T		𝑃^b	𝑁^a	C/C	C/T	T/T	𝑃^b
−427T/C
MR	260	24 (21.8)	236 (22.1)		0.64	130	1 (14.3)	22 (22.9)	107 (22.1)	0.49
Borderline MR	248	20 (18.2)	228 (21.4)			124	0 (0)	20 (20.8)	104 (21.4)
Control	668	66 (60.0)	602 (56.5)			334	6 (85.7)	54 (56.3)	274 (56.5)
	𝑁^a	G	T		𝑃^b	𝑁^a	G/G	G/T	T/T	𝑃^b
−219G/T
MR	260	81 (22.2)	179 (22.0)		0.77	130	16 (26.2)	49 (20.2)	65 (23.6)	0.78
Borderline MR	248	72 (19.8)	176 (21.7)			124	10 (16.4)	52 (21.5)	62 (18.9)
Control	668	211 (58.0)	457 (56.3)			334	35 (57.4)	141 (58.3)	158 (57.4)

aCounts of alleles or genotypes may not add up to total due to excluding the individuals genotyped as 𝜀2/4.
^b𝑃 values are from Mantel-Haenszel 𝜒² test in which MR, borderline MR, and control are ordinal variables.
^c𝜀2+: 𝜀2/𝜀2 + 𝜀2/𝜀3; ε4+: 𝜀3/𝜀4 + 𝜀4/𝜀4.