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3020insC mutation within the NOD2 gene in Crohn's disease: frequency and association with clinical pattern in an Italian population
Correspondence
3020insC frequency
to the Editor
mutation within the NOD2 gene in Crohn’s disease: and association with clinical pattern in an Italian population
Sir Crohn’s disease (CD) is chronic inflammatory disorder of the intestine of unknown aetiology. Recent data l-3 demonstrate that single nucleotide polymorphisms (SNPs) within the NOD2 gene are significantly associated with CD. Indeed, a frameshift mutation caused by a cytosine insertion in the exon 10 of this gene (3020insC) confers an increased risk of developing the disease both in heterozygousity and in homozygousity. We evaluated the frequency of the 3020insC mutation within the NOD2 gene in a sample of CD patients from Southern and Central Italy. Whether or not the presence of this mutation is related to disease variable was also investigated. A total of 133 consecutive CD patients (73 females, median age 43 years, range 17-76), referred from July to October 200 1, were enrolled. All patients were in regular follow-up and the diagnosis of CD was made according to conventional clinical, endoscopical, histological and radiological criteria. A detailed clinical history was obtained for each patient, including: sex, age at enrolment and at diagnosis, familial history of CD (I-II degree), disease duration, type and extent, perianal disease, extraintestinal manifestations, complications and intestinal resections. This CD group included 17 patients with a familial history of CD and 116 patients with sporadic CD. A series of 8 1 healthy volunteers (50 females, median age 47 years, range 2773), with no familial history of CD, were tested as controls. A 3 cc of EDTA blood sample was drawn from each CD patient and healthy subject and the genomic DNA extracted by the phenol-chloroform method. After polymerase chain reaction (PCR) amplification, the presence of 3020insC mutation (+) was assessed by denaturing high-performance liquid chromatography (DHPLC) 3. Written informed consent was obtained, prior to the study, from all CD patients and healthy subjects. Statistical analysis was performed by using Fisher exact test, Chi-squared test or Mann-Withney U test. The relative risk (Odds Ratio) was calculated by logistic regression analysis. The genotypic frequencies of the 3020insC mutation in CD patients and healthy subjects are shown in Table I. This mutation was detected in 19% of CD patients (25/133: 19 heterozygous and 6 homozygous mutant genotype) and in 2.5% of healthy subjects (2/S 1: only heterozygous mutant genotype). No healthy subjects showed the homozygous mutant genotype. In our study population, the presence of the 3020insC mutation confers an overall relative risk of CD of 9.1 [95% confidence interval (CI) 2.1-39.71.
The relative mutation frequency was 2-fold higher in patients with familial history of CD (35.3%, 6/17) than in patients with
sporadic CD (16.4%, 19/l 16). Likewise, the mutation frequency was 2-fold higher in patients with a history of appendectomy (26.1%, 12/46) than in patients with no previous appendectomy (14.9%, 13/87). However, neither of these differences were statistically significant. Patients with or without NOD2 gene 3020insC did not differ in terms of sex distribution (52% and 56% of females, respectively), age at enrolment (median age: 46, range 21-67 vs 42, range 17-76 years), age at diagnosis (median age: 33, range 12-50 vs 27, range 13-68 years) and disease duration (median: 17, range 2-27, range O-41 years). An ileal localisation of the disease was more frequently observed in patients with mutation (18/25,72%) than in those with no mutation (54008, 50%; ~~0.05). A colonic involvement, with or without ileal lesions, was more frequent in patients with no mutation (50/108, 46%) than in those with mutation (5/15, 20%; p
high-perforSNP: single J
P. Uavassori, P. Borgiani, M.R. D’Apice, F. De Nigris, G. Del lfecchio Blanco, I. Monteleone, 1. Biancone, 6. Nouelli, F, Pallone Gastroenterology Unit and Genetic Unit, “Centro di Eccelenza per lo Studio del Rischio Genomico in Patologie Complesse Multifattoriali”< University “Tor Vergata” of Rome, Italy. Fax: +39-06-7259639 1. E-mail: pallone@med. uniroma2. it References
Mle I. Genotypic frequencies [absolute number1 within the NOD2 gene in the study population.
-.I Crohn’s disease In=1331
81.2%
(1081
Healthy subjects
97.5%
[791
of 3020insC
-/+ 14.3%
[I91
+I+
mutation
P
4.5% 61 <0.003
In=811
2.5% (21
0% ICI1
I
’ Hugot JP, Chamaillard M, Zouali H, Lesage S, Cezard JP, Belaiche I, et al. Association of NOD2 leucine-rich repeat variants with the susceptibility to Crohn’s disease. Nature 2001;411:599-603. ’ Ogura Y, Bonen DK, Inohara N, Nicolae DL, Chen FF, Ramos R, et al. A frameshift mutation in NOD2 associated with susceptibility to Crohn’s disease. Nature 2001;411:603-6. 3 Hampe J, Cutnbert A, Croucher PJ, Mirza MM, Mascheretti S, Fisher S, et al. Association between insertion mutation in NOD2 gene and Crohn’s disease in German and British populations. Lancet 2001;357:1925-8.
153
3020insC frequency
to the Editor
mutation within the NOD2 gene in Crohn’s disease: and association with clinical pattern in an Italian population
Sir Crohn’s disease (CD) is chronic inflammatory disorder of the intestine of unknown aetiology. Recent data l-3 demonstrate that single nucleotide polymorphisms (SNPs) within the NOD2 gene are significantly associated with CD. Indeed, a frameshift mutation caused by a cytosine insertion in the exon 10 of this gene (3020insC) confers an increased risk of developing the disease both in heterozygousity and in homozygousity. We evaluated the frequency of the 3020insC mutation within the NOD2 gene in a sample of CD patients from Southern and Central Italy. Whether or not the presence of this mutation is related to disease variable was also investigated. A total of 133 consecutive CD patients (73 females, median age 43 years, range 17-76), referred from July to October 200 1, were enrolled. All patients were in regular follow-up and the diagnosis of CD was made according to conventional clinical, endoscopical, histological and radiological criteria. A detailed clinical history was obtained for each patient, including: sex, age at enrolment and at diagnosis, familial history of CD (I-II degree), disease duration, type and extent, perianal disease, extraintestinal manifestations, complications and intestinal resections. This CD group included 17 patients with a familial history of CD and 116 patients with sporadic CD. A series of 8 1 healthy volunteers (50 females, median age 47 years, range 2773), with no familial history of CD, were tested as controls. A 3 cc of EDTA blood sample was drawn from each CD patient and healthy subject and the genomic DNA extracted by the phenol-chloroform method. After polymerase chain reaction (PCR) amplification, the presence of 3020insC mutation (+) was assessed by denaturing high-performance liquid chromatography (DHPLC) 3. Written informed consent was obtained, prior to the study, from all CD patients and healthy subjects. Statistical analysis was performed by using Fisher exact test, Chi-squared test or Mann-Withney U test. The relative risk (Odds Ratio) was calculated by logistic regression analysis. The genotypic frequencies of the 3020insC mutation in CD patients and healthy subjects are shown in Table I. This mutation was detected in 19% of CD patients (25/133: 19 heterozygous and 6 homozygous mutant genotype) and in 2.5% of healthy subjects (2/S 1: only heterozygous mutant genotype). No healthy subjects showed the homozygous mutant genotype. In our study population, the presence of the 3020insC mutation confers an overall relative risk of CD of 9.1 [95% confidence interval (CI) 2.1-39.71.
The relative mutation frequency was 2-fold higher in patients with familial history of CD (35.3%, 6/17) than in patients with
sporadic CD (16.4%, 19/l 16). Likewise, the mutation frequency was 2-fold higher in patients with a history of appendectomy (26.1%, 12/46) than in patients with no previous appendectomy (14.9%, 13/87). However, neither of these differences were statistically significant. Patients with or without NOD2 gene 3020insC did not differ in terms of sex distribution (52% and 56% of females, respectively), age at enrolment (median age: 46, range 21-67 vs 42, range 17-76 years), age at diagnosis (median age: 33, range 12-50 vs 27, range 13-68 years) and disease duration (median: 17, range 2-27, range O-41 years). An ileal localisation of the disease was more frequently observed in patients with mutation (18/25,72%) than in those with no mutation (54008, 50%; ~~0.05). A colonic involvement, with or without ileal lesions, was more frequent in patients with no mutation (50/108, 46%) than in those with mutation (5/15, 20%; p
high-perforSNP: single J
P. Uavassori, P. Borgiani, M.R. D’Apice, F. De Nigris, G. Del lfecchio Blanco, I. Monteleone, 1. Biancone, 6. Nouelli, F, Pallone Gastroenterology Unit and Genetic Unit, “Centro di Eccelenza per lo Studio del Rischio Genomico in Patologie Complesse Multifattoriali”< University “Tor Vergata” of Rome, Italy. Fax: +39-06-7259639 1. E-mail: pallone@med. uniroma2. it References
Mle I. Genotypic frequencies [absolute number1 within the NOD2 gene in the study population.
-.I Crohn’s disease In=1331
81.2%
(1081
Healthy subjects
97.5%
[791
of 3020insC
-/+ 14.3%
[I91
+I+
mutation
P
4.5% 61 <0.003
In=811
2.5% (21
0% ICI1
I
’ Hugot JP, Chamaillard M, Zouali H, Lesage S, Cezard JP, Belaiche I, et al. Association of NOD2 leucine-rich repeat variants with the susceptibility to Crohn’s disease. Nature 2001;411:599-603. ’ Ogura Y, Bonen DK, Inohara N, Nicolae DL, Chen FF, Ramos R, et al. A frameshift mutation in NOD2 associated with susceptibility to Crohn’s disease. Nature 2001;411:603-6. 3 Hampe J, Cutnbert A, Croucher PJ, Mirza MM, Mascheretti S, Fisher S, et al. Association between insertion mutation in NOD2 gene and Crohn’s disease in German and British populations. Lancet 2001;357:1925-8.
153