ABCB9 polymorphism rs61955196 is associated with schizophrenia in a Chinese Han population

Table 1 Association analysis for four target single-nucleotide polymorphisms and schizophrenia risk, n (%)¹

SNP	Genotype/allele	SCZ (n = 443)	HC (n = 511)	P value	OR (95%CI)	HWE test for controls
rs11917047 (PTPRG)	AA	219 (49.4)	259 (50.7)		1.00 (ref)	0.151
	AG	183 (41.3)	200 (39.1)	0.431	1.12 (0.85-1.47)
	GG	41 (9.3)	52 (10.2)	0.713	0.92 (0.58-1.45)
	A	621 (70.1)	718 (70.3)		1.00 (ref)
	G	265 (29.9)	304 (29.7)	0.885	1.02 (0.83-1.24)
rs2239681 (IGF2)	AA	156 (35.2)	177 (34.6)		1.00 (ref)	0.104
	AG	211 (47.6)	232 (45.4)	0.667	1.07 (0.80-1.43)
	GG	76 (17.2)	102 (20.0)	0.447	0.87 (0.59-1.26)
	A	523 (59.0)	586 (57.3)		1.00 (ref)
	G	363 (41.0)	436 (42.7)	0.567	0.95 (0.79-1.14)
rs3842756 (INSIGF)	CC	405 (91.4)	475 (93.0)		1.00 (ref)	0.409
	CT	38 (8.6)	36 (7.0)	0.319	1.28 (0.79-2.08)
	TT	-	-	-	-
	C	848 (95.7)	986 (96.5)		1.00 (ref)
	T	38 (4.3)	36 (3.5)	0.329	1.27 (0.79-2.04)
rs61955196 (ABCB9)	CC	157 (35.4)	202 (39.5)		1.00 (ref)	0.513
	CG	213 (48.1)	244 (47.7)	0.297	1.16 (0.88-1.55)
	GG	73 (16.5)	65 (12.7)	0.037a	1.54 (1.03-2.30)
	C	527 (59.5)	648 (63.4)		1.00 (ref)
	G	359 (40.5)	374 (36.6)	0.042a	1.22 (1.01-1.47)

^aP < 0.05.

¹Adjusted for gender.

SCZ: Schizophrenia; HC: Healthy control; OR: Odds ratio; HWE: Hardy-Weinberg equilibrium; SNP: Single-nucleotide polymorphism.

Table 2 Associations between rs61955196 and schizophrenia based on multiple models, n (%)¹

Model	Genotype	SCZ (%)	HC (%)	OR (95%CI)	P value	AIC	BIC
Codominant	CC	157 (35.4)	202 (39.5)	1.00		1279.8	1299.2
	GC	213 (48.1)	244 (47.8)	1.16 (0.88-1.55)	0.297
	GG	73 (16.5)	65 (12.7)	1.54 (1.03-2.30)	0.037a
Dominant	CC	157 (35.4)	202 (39.5)	1.00	0.120	1279.7	1294.3
	GC + GG	286 (64.6)	309 (60.5)	1.24 (0.95-1.62)
Recessive	CC + GC	370 (83.5)	446 (87.3)	1.00	0.068	1278.9	1293.5
	GG	73 (16.5)	65 (12.7)	1.41 (0.97-2.04)
Overdominant	CC + GG	230 (51.9)	267 (52.2)	1.00	0.810	1282.1	1296.7
	GC	213 (48.1)	244 (47.8)	1.03 (0.80-1.34)
Log-additive	-	-	-	1.22 (1.01-1.48)	0.040a	1278	1292.6

^aP < 0.05.

¹Adjusted for gender.

SCZ: Schizophrenia; HC: Healthy control; OR: Odds ratio; AIC: Akaike information criterion; BIC: Bayesian information criterion.

Table 3 Association analysis for famine and single-nucleotide polymorphisms, n (%)¹

Group	SNP	Genotype	Famine	Non-famine	P value	OR (95%CI)
SCZ	rs11917047	AA + GA	204 (92.7)	198 (88.8)	0.150	1.00
	(Recessive)	GG	16 (7.3)	25 (11.2)		1.62 (0.84-3.13)
	rs2239681	AA + GA	185 (84.1)	182 (81.6)	0.550	1.00
	(Recessive)	GG	35 (15.9)	41 (18.4)		1.16 (0.71-1.91)
	rs3842756	CC	198 (90)	207 (92.8)	0.270	1.00
	(Codominant)	CT	22 (10)	16 (7.2)		0.68 (0.35-1.34)
	rs61955196	CC + GG	117 (53.2)	113 (50.7)	0.610	1.00
	(Overdominant)	GC	103 (46.8)	110 (49.3)		1.10 (0.76-1.60)
HC	rs11917047	AA + GA	249 (91.5)	210 (87.9)	0.160	1.00
	(Recessive)	GG	23 (8.5)	29 (12.1)		1.50 (0.84-2.68)
	rs2239681	AA + GA	222 (81.6)	187 (78.2)	0.330	1.00
	(Recessive)	GG	50 (18.4)	52 (21.8)		1.24 (0.80-1.92)
	rs3842756	CC	257 (94.5)	218 (91.2)	0.150	1.00
	(Codominant)	CT	15 (5.5)	21 (8.8)		1.65 (0.83-3.27)
	rs61955196	CC + GG	144 (52.9)	123 (51.5)	0.750	1.00
	(Overdominant)	GC	128 (47.1)	116 (48.5)		1.06 (0.75-1.50)

¹Adjusted for gender.

SCZ: Schizophrenia; HC: Healthy control; OR: Odds ratio; SNP: Single-nucleotide polymorphism.

Table 4 Generalized multifactor dimensionality reduction analysis for best interaction combination models

No.	Best combination	CVC	Te-BA	P value
1	rs61955196	9/10	0.5097	0.8281
2	rs2239681 × rs61955196	10/10	0.5582	0.0547
3	rs11917047 × rs2239681 × rs61955196	10/10	0.5341	0.1719
4	rs11917047 × rs2239681 × rs3842756 × rs61955196	10/10	0.5449	0.1719

CVC: Cross validation consistency; Te-BA: Testing-balanced accuracy.

Table 5 Crossover analysis of interactions between rs11917047/rs2239681/rs3842756/ rs61955196 and famine factor with schizophrenia

SNP	Genotype	Famine	SCZ	HC	OR (95%CI)	P value
rs11917047	AG + GG	+	121	119	1.21 (0.85-1.72)	0.294
	AG + GG	-	103	133	0.92 (0.65-1.31)	0.646
	AA	+	102	120	1.01 (0.70-1.45)	0.958
	AA	-	117	139	1.00 (ref)
rs2239681	AG + GG	+	144	157	1.13 (0.78-1.65)	0.519
	AG + GG	-	143	177	1.00 (0.69-1.45)	0.986
	AA	+	79	82	1.19 (0.77-1.83)	0.432
	AA	-	77	95	1.00 (ref)
rs3842756	CT	+	16	21	0.99 (0.50-1.95)	0.974
	CT	-	22	15	1.90 (0.96-3.77)	0.064
	CC	+	207	218	1.23 (0.95-1.61)	0.123
	CC	-	198	257	1.00 (ref)
rs61955196	CG + GG	+	147	145	1.35 (0.94-1.95)	0.109
	CG + GG	-	139	164	1.13 (0.78-1.63)	0.513
	CC	+	76	94	1.08 (0.71-1.64)	0.724
	CC	-	81	108	1.00 (ref)

SCZ: Schizophrenia; HC: Healthy control; OR: Odds ratio; SNP: Single-nucleotide polymorphism.