Inducible Nitric Oxide Synthase iNOS-954-G>C and Ex16+14-C>T Gene Polymorphisms and Susceptibility to Vitiligo in the Saudi Population

Figures & data

Table 1 Demographical Characteristics of Vitiligo Patients and Controls

Characteristics	Vitiligo Patients (N = 120)	Controls (N = 120)
Age of patients (years, mean ± SD)	27.04 ± 12.32	28.68 ±12.12
Gender
Male	61 (50.83%)	64 (50%)
Female	59 (49.16%)	56 (50%)
Age of onset (years)	22.51 ± 15.40	NA
Duration of disease (mean age in years)	6.2 (1–19)
Family history of vitiligo
Present	18/120 (15%)
Absent	102/120 (85%)
History of autoimmune disease
Present	8/120 (6.67%)
Absent	112/120 (93.33%)
Type of vitiligo	N (%)
Generalized	40 (33.33%)
Focal	40 (33.33%)
Acrofacial	23 (19.16%)
Lip tip	15 (12.5%)
Universalis	2 (1.66%)

Note: Figure in parenthesis shows the percentage values.

Table 2 Genotypic Frequencies of rs1800482 G>C and rs2297518 C>T in Cases and Controls and Their Associations with Risk of Vitiligo

Genotypes/Allele	Controls, N = 120 (%)	Cases, N = 120 (%)	Odds Ratio (OR)	95% CI	p-value	^pHWE
rs1800482 G>C						0.754**
GG	68 (56.67)	35 (29.16)	Ref	-	-	0.612***
GC	45 (37.50)	77 (64.16)	3.46	1.99–6.01	0.001*
CC	7 (5.83)	8 (6.68)	2.28	0.765–6.83	0.139
GC+CC	52 (43.33)	85 (70.83)	3.30	1.93–5.65	0.001*
G	181 (75.41)	147 (61.25)	Ref	-
C	59 (24.58)	93 (38.75)	1.94	1.31–2.87	0.001*
rs2297518 C>T						0.804**
CC	76 (63.33)	70 (58.33)	Ref	-	-	0.775***
CT	41 (34.17)	46 (38.33)	1.19	0.707–2.03	0.501
TT	3 (2.50)	4 (3.33)	1.60	0.261–9.90	0.609
CT+TT	44 (36.67)	50 (41.67)	1.21	0.724–2.04	0.458
C	193 (80.42)	186 (77.5)	Ref	-
T	47 (19.58)	54 (22.5)	1.19	0.767–1.85	0.501

Notes: The Binary logistic regression analysis was performed for variants analysis of rs1800482 G>C and rs2297518 C>T, GG & CC = common genotypes, GC & CT = heterozygous genotypes, CC & TT = homozygous variants genotypes. After Bonferroni correction, p*< 0.005 was declared statistically significant. ^pHWE <0.05 are not consistent, **^pHWE for controls, ***^pHWE for patients, figure in parenthesis indicate percent values.

Table 3 Combined Genotypes Analysis of rs1800482 G>C and rs2297518 C>T in Cases and Controls

Combined Genotypes of rs1800482 and rs2297518	Controls, N = 120 (%)	Cases, N = 120 (%)	OR	95% CI	p- value
GG/CC	44 (36.67)	18 (15.0)	Ref	-	-
GG/CT	22 (18.33)	15 (12.5)	1.66	0.708–3.91	0.274
GG/TT	2 (1.67)	1 (0.83)	1.22	0.104–14.33	1.00
GC/CC	26 (21.67)	48 (40)	4.51	2.18–9.33	0.001*
GC/CT	19 (15.83)	28 (23.33)	3.60	1.61–8.01	0.001*
GC/TT	0	2 (1.67)	ND	-	-
CC/CC	6 (5.0)	4 (3.33)	1.62	0.410–6.47	0.713
CC/CT	1 (0.83)	4 (3.33)	9.77	1.02–93.6	0.036
CC/TT	0	0	ND	-	-

Notes: The Chi square test was performed for polymorphic analysis of combined genotypes, GG & CC = common genotypes, GC & CT = heterozygous genotypes, CC & TT = homozygous variants genotypes, *p < 0.005 was considered statistically significant after Bonferroni correction, figure in parenthesis indicate percent values.

Table 4 Comparison of Genotypic Frequencies of rs1800482 G>C and rs2297518 C>T in Male and Female Cases of Vitiligo

Genotypes/Allele	Male	Female	OR	95% CI	p- value
	N = 61 (%)	N = 59 (%)
rs1800482 G>C
GG	16 (26.22)	18 (30.50)	Ref
GC	42 (68.85)	37 (62.71)	1.27	0.57–2.85	0.378
CC	03 (4.91)	04 (6.78)	0.843	0.16–4.35	0.881
GC+CC	45 (73.78)	41 (69.49)	1.23	0.56–2.73	0.375
G	74 (60.66)	73 (61.86)	Ref
C	48 (39.34)	45 (38.13)	1.05	0.62–1.77	0.476
rs2297518 C>T
CC	35 (57.38)	36 (61.02)	Ref
CT	25 (40.98)	20 (33.90)	1.28	0.60–2.72	0.320
TT	01 (1.63)	03 (5.08)	0.34	0.034–3.42	0.338
CT+TT	26 (42.62)	23 (38.98)	1.16	0.56–2.41	0.413
C	95 (77.87)	92 (77.97)	Ref
T	27 (22.13)	26 (22.03)	1.05	0.54–1.185	0.554

Notes: The Binary logistic regression analysis was performed for polymorphic analysis of rs1800482 G>C and rs2297518 C>T, GG & CC = common genotypes, GC & CT = heterozygous genotypes, CC & TT = homozygous variant genotypes, p < 0.005 was considered statistically significant (after Bonferroni correction), figure in parenthesis indicate percent values.

Table 5 Comparison of Genotypic Frequencies of rs1800482 G>C and rs2297518 C>T Between Two Groups of Onset Age in Vitiligo Patients

Genotypes/Allele	≤ 30 Years	>30 Years	OR	95% CI	p- value
	N = 57 (%)	N = 63 (%)
rs1800482 G>C
GG	20 (35.09)	23 (36.50)	Ref
GC	32 (56.14)	33 (52.38)	1.11	0.515–2.41	0.468
CC	05 (8.77)	07 (11.12)	0.821	0.225–2.99	0.514
GC+CC	37 (64.91)	40 (63.49)	1.06	0.503–2.24	0.511
G	72 (63.15)	79 (62.69)	Ref
C	42 (36.84)	47 (37.30)	0.980	0.580–1.77	0.524
rs2297518 C>T
CC	38 (66.67)	35 (55.56)	Ref
CT	15 (26.32)	23 (36.50)	0.600	0.270–1.38	0.144
TT	04 (7.01)	05 (7.94)	0.736	0.83–2.96	0.468
CT+TT	19 (33.34)	28 (44.45)	0.625	0.297–1.31	0.145
C	91 (79.82)	93 (73.81)	Ref
T	23 (20.18)	33 (26.19)	0.712	0.388–1.30	0.171

Notes: The Binary logistic regression analysis was performed for polymorphic analysis of rs1800482 G>C and rs2297518 C>T, GG & CC = common genotypes, GC & CT = heterozygous genotypes, CC & TT = homozygous variant genotypes, p < 0.005 was considered statistically significant (after Bonferroni correction), figure in parenthesis indicate percent values.

Table 6 Comparison of Genotypic Frequencies of rs1800482 G>C and rs2297518 C>T Among Different Types of Vitiligo Type of Vitiligo

	Generalized	Focal	Acrofacial	Lip Tip	Universalis	p- value
	N = 40	N = 40	N = 23	N = 15	N = 2
rs1800482G>C
GG	09 (22.50)	07 (17.50)	06 (26.08)	03 (20.00)	0.0 (0.00)	0.885
GC	28 (70.00)	27 (67.50)	15 (65.21)	10 (66.67)	01 (50.00)
CC	03 (7.50)	06 (15.00)	02 (08.71)	02 (13.33)	01 (50.00)
GC+CC	31 (77.50)	33 (82.50)	17 (73.91)	12 (80.00)	02 (100.0)	0.920
G	46 (57.50)	41 (51.25)	27 (58.70)	16 (53.33)	01 (25.00)	0.646
C	34 (42.50)	39 (48.75)	19 (41.30)	14 (46.67)	03 (75.00)
rs2297518 C>T
CC	8 (20.00)	10 (25.00)	05 (21.73)	02 (13.33)	01 (50.00)	0.862
CT	30 (75.00)	26 (65.00)	16 (69.57)	12 (80.00)	01 (50.00)
TT	02 (5.00)	04 (10.00)	02 (8.69)	01 (6.67)	0.0 (0.00)
CT+TT	32 (80.00)	23 (57.50)	18 (78.26)	13 (86.67)	01 (50.00)	0.624
C	46 (57.50)	46 (57.50)	26 (56.52)	16 (53.33)	02 (50.00)	0.841
T	34 (42.50)	34 (42.50)	20 (43.48)	14 (46.67)	02 (50.00)

Notes: Fisher’s exact test was performed for polymorphic analysis of rs1800482 G>C and rs2297518 C>T, GG & CC = common genotypes, GC & CT = heterozygous genotypes, CC & TT = homozygous variant genotypes, p < 0.005 was considered statistically significant (after Bonferroni correction), figure in parenthesis indicate percent values.