Severity of ulcerative colitis is associated with a polymorphism at diamine oxidase gene but not at histamine N-methyltransferase gene

Table 1 HNMT genotypes and allele frequencies among overall UC patients and healthy controls

Genotype	UC patients		Healthy controls		OR (95% CI)	p
	n	% (95% CI)	n	% (95% CI)
C / C	161	82.6 (77.2-87.9)	193	78.8 (73.7-83.9)	1.27 (0.79-2.05)	0.33
C / T	32	16.4 (11.2-21.6)	48	19.6 (14.6-24.6)	0.75 (0.45-1.23)	0.34
T / T	2	1.0 (0-2.4)	4	1.6 (0-3.2)	0.60 (0.13-2.85)	0.50
Total subjects	195		245
C allele	354	90.8 (87.9-93.6)	434	88.6 (85.8-91.4)	1.27 (0.80-2.02)	0.29
T allele	36	9.2 (6.4-12.1)	56	11.4 (8.6-14.2)
Total alleles	390		490

Table 2 ABP1 genotypes and allele frequencies among overall UC patients and healthy controls

Genotype	UC patients		Healthy controls		OR (95% CI)	p
	n	% (95% CI)	n	% (95% CI)
C/C	101	44.1 (37.7-50.5)	137	52.5 (46.4-58.5)	0.71 (0.49-1.04)	0.064
C/G	115	50.2 (43.7-56.7)	108	41.4 (35.4-47.3)	1.43 (0.98-2.08)	0.050
G/G	13	5.7 (2.7-8.7)	16	6.1 (3.2-9.0)	0.92 (0.41-2.08)	0.832
Total subjects	229		261
C allele	317	69.2 (65.0-73.4)	382	73.2 (69.4-77.0)	1.21 (0.92-1.60)	0.17
G allele	141	30.8 (26.6-35.0)	140	26.8 (23.0-30.6)
Total alleles	458		522

Table 3 Phenotypic characteristics among UC patients classified as carriers or non-carriers of mutations at the ABP1 gene

Phenotypic characteristics	Carriersn = 128	Non-carriersn = 101	OR (95%CI)p value
Male:Female	76:52	62:39	0.79 (0.52-1.62) 0.86
Mean age at diagnosis, yr (range)	37.9 (6-83)	37.1 (17-81)	P = 0.64
Mean duration of disease, yr (range)	11.5 (2-39)	11.0 (2-41)	P = 0.58
Family history of IBD, n (%)	31 (24.2)	21 (20.8)	1.22 (0.62-2.39) 0.54
Smokers at diagnosis, n (%)	28 (21.9)	22 (21.8)	1.01 (0.51-1.98) 0.99
Previous appendectomy, n (%)	5 (3.9)	6 (6.9)	0.64 (0.16-2.47) 0.54
Previous tonsillectomy, n (%)	11 (8.6)	14 (13.9)	0.58 (0.23-1.55) 0.29
Extent of UC
Extensive, n (%)	53 (41.4)	42 (41.6)	1.33 (0.77-2.30) 1
Non-extensive, n (%)	75 (58.6)	59 (58.4)
Extraintestinal clinical manifestations
Cutaneous, n (%)	23 (17.9)	10 (9.9)	1.99 (0.85-4.76) 0.09
Articular, n (%)	49 (38.3)	28 (27.7)	1.64 (0.90-2.99) 0.09
Ocular, n (%)	3 (2.3)	4 (3.9)	0.58 (0.10-3.17) 0.7
Hepatic, n (%)	31 (24.2)	14 (13.9)	1.99 (0.94-4.22) 0.07
Therapy categories
Immunosuppressants, n (%)	41 (70)	17 (30)	2.41 (1.21-4.83) 0.006
Surgery, n (%)1	19 (83)	4 (17)	2.50 (1.28-4.91) 0.003

¹Eighteen of these patients are also included in the subgroup of patients receiving immunosuppressive therapy. Four of the remaining 5 patients in the surgery group were carriers of the variant ABP1 allele.

Table 4 Phenotypic among UC patients classified as carriers or non-carriers of mutations at the HNMT gene

Phenotypic characteristics	Carriersn = 34	Non-carriersn = 161	OR (95% CI)p value
Male:Female	20:14	91:70	1.10 (0.49-2.49) 0.81
Mean age at diagnosis, yr (range)	35 (6-83)	38 (17-81)	P = 0.24
Mean duration of disease, yr (range)	12.4 (2-39)	11.3 (2-41)	P = 0.11
Family history of IBD, n (%)	8 (23.5%)	35 (21.7%)	1.11 (0.42-2.85) 0.82
Smokers at diagnosis, n (%)	8 (23.5%)	31 (19.3%)	1.29 (0.48-3.36) 0.57
Previous appendectomy, n (%)	2 (5.9%)	6 (3.7%)	1.61 (0.21-9.47) 0.63
Previous tonsillectomy, n (%)	2 (5.9%)	17 (10.5%)	0.53 (0.08-2.57) 0.54
Extent of UC
Extensive, n (%)	15 (44.1%)	64 (39.8%)	1.20 (0.53-2.69) 0.63
Non-extensive, n (%)	19 (55.9%)	97 (60.2%)
Extraintestinal manifestations
Cutaneous, n (%))	6 (17.6%)	19 (11.8%)	1.60 (0.52-4.66) 0.4
Articular, n (%)	15 (44.1%)	47 (29.2%)	1.91 (0.84-4.35) 0.09
Ocular, n (%)	1 (2.9%)	5 (3.1%)	0.95 (0.02-8.86) 1
Hepatic, n (%)	5 (14.7%)	27 (16.8%)	0.86 (0.26-2.60) 0.77
Therapy categories
Immunosuppressants, n (%)	8 (23.5%)	37 (23%)	1.031 (0.39-2.65) P = 0.94
Surgery, n (%)	6 (17.6%)	16 (9.94%)	1.941 (0.62-5.91) 0.20

¹As compared with the remaining patients.