Tumor necrosis factor-α and -β genetic polymorphisms as a risk factor in Saudi patients with schizophrenia

Figures & data

Table 1 Genotype and allele frequencies of TNF-α (−308G/A) variants in schizophrenia patients and matched controls

Genotype/allele	Schizophrenia (n=180)		Control (n=200)		P-valuea,b	RR	EFc/PF
	n	%	n	%
GG	4	2.22	110	55	<0.0001	0.042	0.444
GA	176	97.78	76	38	<0.0001	71.789	0.688c
AA	0	0.00	14	7	0.0001	–	–
G-allele (TNF-α 1-allele)	184	51.11	296	74	<0.0001	0.367	0.389
A-allele (TNF-α 2-allele)	176	48.89	104	26	<0.0001	2.722	0.397c

Notes:

a Statistically significant using Fisher’s exact test.

b P=0.0005, Bonferroni corrected.

c Data for EF.

Abbreviations: TNF, tumor necrosis factor; n, number of subjects; RR, relative risk; EF, etiologic fraction; PF, preventive fraction.

Table 3 Genotype and allele frequencies of TNF-β (−252A/G) polymorphism in male and female patients

Genotype/allele	Female (n=53)		Male (n=127)		P-value	RR
	n	%	n	%
GG	2	3.77	20	15.75	0.025a,b	0.209
GA	49	92.46	95	74.80	0.007a,c	4.126
AA	2	3.77	12	9.45	0.238	0.376
G-allele	53	50.00	135	53.15	0.643	0.881
A-allele	53	50.00	119	46.85	0.643	1.134

Notes:

a Statistically significant using Fisher’s exact test.

b P=0.05, Bonferroni corrected.

c P=0.01, Bonferroni corrected.

Abbreviations: TNF, tumor necrosis factor; n, number of subjects; RR, relative risk.

Figure 1 Amplification of TNF-α (−308G/A) alleles (G and A).

Notes: Lane M: 100 bp DNA marker; lanes 1 and 3: amplification of allele G; lanes 2 and 6: amplification of allele A; 184 bp band for target DNA and 329 bp band for internal control.
Abbreviation: TNF, tumor necrosis factor.

Figure 2 Amplification of TNF-β (+252A/G) alleles (A and G).

Notes: Lane M: 100 bp DNA marker; lanes 1, 3, and 5: amplification of allele G; lanes 4 and 6: amplification of allele A; 94 bp band for target DNA and 240 bp band for internal control.
Abbreviation: TNF, tumor necrosis factor.

Table 4 Genotype and allele frequencies of TNF-β (LT-α) intron 1 +252 variants in schizophrenia patients and matched controls

Genotype/allele	Schizophrenia (n=180)		Control (n=200)		P-value	RR	EFa/PF
	n	%	n	%
GG	22	12.22	28	14	0.650	0.855	0.744
GA	144	80.00	148	74	0.181	1.405	0.142a
AA	14	7.78	24	12	0.230	0.618	0.185
G-allele (TNF-β 1-allele)	188	52.22	204	51	0.771	1.050	0.023a
A-allele (TNF-β 2-allele)	172	47.78	196	49	0.771	0.952	0.229

Note:

a Data for EF.

Abbreviations: TNF, tumor necrosis factor; LT-α, lymphotoxin-alpha; n, number of subjects; RR, relative risk; EF, etiologic fraction; PF, preventive fraction.

Table 2 Genotype and allele frequencies of TNF-β (LT-α) intron 1 +252 variants in Schizophrenia patients with negative or positive symptoms and matched controls

Genotype/allele	With negative symptoms (n=94)		With positive symptoms (n=86)		Control (n=200)
	n	%	n	%	n	%
GG	11	11.70	11	12.79	28	14
GA	79	84.04	65	75.58	148	74
AA	4	4.26a,b	10	11.63	24	12
G-allele	101	53.72	87	50.58	204	51
A-allele	87	46.28	85	49.42	196	49

Notes:

a P=0.034 as compared to controls (using Fisher’s exact test).

b P=0.034, Bonferroni corrected.

Abbreviations: TNF, tumor necrosis factor; LT-α, lymphotoxin-alpha; n, number of subjects.