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Lack of association between estrogen receptor 1 gene polymorphisms and multiple sclerosis in southern Italy in humans
Neuroscience Letters 327 (2002) 115–118 www.elsevier.com/locate/neulet
Lack of association between estrogen receptor 1 gene polymorphisms and multiple sclerosis in southern Italy in humans Giovanni Savettieri a, Rita Cittadella b, Paola Valentino c, Ida Manna b, Virginia Andreoli b, Antonella La Russa b, Gaetana La Porta b, Francesca Ruscica c, Paolo Ragonese a, Domenico Pirritano c, Simona Bonavita d, Gioacchino Tedeschi d, Aldo Quattrone b,c,* a Institute of Neurology, University of Palermo, Palermo, Italy Institute of Neurological Sciences, National Research Council, Mangone (Cosenza), Italy c Institute of Neurology, Policlinico Mater Domini, University Magna Graecia, Catanzaro, Italy d 2nd Department of Neurology, 2nd University of Naples, Naples, Italy b
Received 8 October 2001; received in revised form 5 April 2002; accepted 11 April 2002
Abstract Estrogen receptor 1 gene polymorphisms (ESR1) have been found to be associated with multiple sclerosis (MS) in both Japanese and Finnish populations. We investigated the association between ESR1 polymorphisms (PvuII and XbaI) and MS in a study of 132 MS patients and 129 controls from the same geographic background (southern Italy). Allelic and genotypic frequencies were not different between MS patients and population controls for either the PvuII or XbaI polymorphism. This result suggests that the association between a given disease and a genomic characteristic must be confirmed by separate investigations in different populations. q 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Multiple sclerosis; Estrogen receptor; Polymorphism; Italians; Genetic susceptibility
There are many reasons to suppose that sexual hormones may play a role in multiple sclerosis (MS): the frequency of MS is higher in women [3]; MS onset occurs more frequently during the reproductive years [5]; and the period of gestation is considered at low risk for relapse in women affected by MS [4]. On the contrary, however, the puerperium is considered at high risk [1,4]. Studies have shown that estrogens are able to inhibit the progression of experimental allergic encephalomyelitis (EAE), i.e. the experimental model of MS [7]. In addition, estriol treatment reduces the severity of EAE [8]. Estrogens act through interaction with nuclear receptors, and previous studies have determined the structure of the estrogen receptor 1 gene (ESR1) [6,10]. A positive association between ESR1 and MS has been recently reported. Niino et al. [12] have shown an association between the ESR1 PvuII polymorphism and a higher susceptibility in Japanese patients to acquiring MS, and Mattila et al. [11] suggested an association between the pp genotype of the * Corresponding author. Tel.: 139-961-775-322; fax: 139-961777-775. E-mail address: [email protected] (A. Quattrone).
PvuII polymorphism of the ESR1 gene and the human leukocyte antigen (HLA)-DR2 with MS. In our study we investigated the association between ESR1 gene polymorphisms and MS to verify whether or not the association found in both the Japanese and Finnish MS patients was confirmed in an ethnically different population. Blood was collected from 132 MS patients (51 men and 81 women) and 129 healthy controls (63 men and 66 women). Patients with MS were consecutively selected among the outpatients attending the Institute of Neurology at the University of Catanzaro, Italy. Informed consent was obtained from all patients and healthy controls. Among these individuals, 104 were affected by the relapsing-remitting form, 21 by a secondary progressive form, and seven by a primary progressive form. The median age was 38.5 (range 15–78); the median age at onset of the disease was 25 years (range 15–54). The control group had a median age of 30 years (range 18–48). All patients and controls were born in Calabria and had lived in southern Italy for many generations. Diagnosis of MS was made according to Poser’s criteria [13]. Genomic DNA was extracted from EDTA blood samples
0304-3940/02/$ - see front matter q 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S03 04 - 394 0( 0 2) 00 41 0- X
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Table 1 Estrogen receptor 1 polymorphisms in MS patients and controls MS patients (%) Genotype frequencies (PvuII) PP pp Pp Allele frequencies P p Genotype frequencies (XbaI) XX xx Xx Allele frequencies X x
Controls (%)
x2
P
23 (17.4) 42 (31.8) 67 (50.8)
24 (18.6) 34 (26.4) 71 (55.0)
0.01 1.57 0.32
0.93 0.21 0.57
113 (42.8) 151 (57.2)
119 (46.1) 139 (53.9)
0.46 0.46
0.50 0.50
26 (19.7) 40 (30.3) 66 (50.0)
22 (17.1) 35 (27.1) 72 (55.8)
0.15 0.71 0.91
0.70 0.40 0.34
118 (44.7) 146 (55.3)
116 (45.0) 142 (55.0)
by a standard phenol-chloroform extraction procedure. ESR1 gene polymorphisms were determined by PvuII and XbaI restriction endonuclease digestion of polymerase chain reaction (PCR) products, as described by Kobayashi et al. [9]. The PCR products that contained a part of intron 1 and exon 2 of the ESR1 gene were digested for 4 h with PvuII and XbaI (Roche) at 378C, producing fragments of 1300 bp (P allele) or 850 1 450 bp (p allele), and of 1300 bp (X allele) or 900 1 400 bp (x allele), respectively. The presence of the restriction site for each endonuclease was conventionally indicated with a lowercase letter (p or x, respectively, for PvuII and XbaI endonucleases) while an uppercase letter (P or X) indicated the absence of the restriction site. The different alleles of patients and controls were compared by the Chi 2 test and Fisher exact test. The Hardy–Weinberg equilibrium was tested for both polymorphisms by standard x 2 goodness of fit test. The relative risk for each polymorphism was estimated through the
calculation of odds ratio (OR). All ORs were adjusted for sex using logistic regression models. For each OR, a 95% confidence interval (CI) was computed and statistical tests were performed by computing two-sided P values. We estimated that with a difference in frequency of P allele between cases and controls greater than 13% the number of individuals of our sample gave sufficient statistical power (more than 80%) to detect the difference at 0.05 (two-tailed) level. All statistical analyses were performed with SPSS software for Windows 95/98 (version 10.0.7, SPSS, Chicago, IL). The distribution of PvuII and XbaI genotypes in control subjects was very similar to that previously reported in an Italian population [2]. The genotype distribution was in Hardy–Weinberg equilibrium both in controls (PvuII, P ¼ 0:222; XbaI, P ¼ 0:147) and MS subjects (PvuII, P ¼ 0:274; XbaI, P ¼ 0:896). A strong linkage disequilibrium between PvuII and XbaI polymorphisms was detected in MS patients (P , 0:00001, D 0 ¼ 0:86) as well as in controls (P , 0:00001, D 0 ¼ 0:93).
Table 2 Association between MS and XbaI polymorphism Genotype
xx versus XX Xx versus XX xx and Xx versus XX: total sample xx versus Xx and XX: total sample Age at onset #25 years b Age at onset .25 years b a
Genotype frequency Cases (N ¼ 132)
Controls (N ¼ 129)
40/66 66/92 106/132 40/132 54/67 51/64
35/57 72/94 107/129 35/129 94/129 94/129
Odds ratio (CI) a
P value
1.11 (0.83–1.48) 1.57 (0.92–2.70) 0.70 (0.42–1.16) 1.13 (0.74–1.72) 1.25 (0.64–2.43) 0.80 (0.41–1.56)
0.48 0.10 0.17 0.56 0.50 0.50
Odds ratios were adjusted by sex using logistic regression, because cases and controls were not matched by sex. The analysis was made by stratifying cases (xx and Xx versus XX) by median age at onset of MS. Age at onset was unknown in one case. b
G. Savettieri et al. / Neuroscience Letters 327 (2002) 115–118
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Table 3 Association between MS and PvuII polymorphism Genotype
pp versus PP Pp versus PP pp and Pp versus PP: total sample pp versus Pp and PP: total sample Age at onset #25 years b,c Age at onset .25 years a,b
Genotype frequency Cases (N ¼ 132)
Controls (N ¼ 129)
42/65 67/90 109/132 42/132 56/67 52/64
34/58 71/95 105/129 34/129 105/129 105/129
Odds ratio (CI) a
P value
1.30 (0.74–2.27) 0.91 (0.53–1.55) 1.01 (0.61–1.67) 1.27 (0.83–1.94) 1.26 (0.62–2.55) 0.79 (0.39–1.60)
0.36 0.74 0.98 0.26 0.52 0.52
a
Odds ratios were adjusted by sex using logistic regression, because cases and controls were not matched by sex. The analysis was made by stratifying cases (pp or Pp versus PP) by median age at onset of MS. Age at onset was unknown in one case. c Stratification was restricted to cases because the variable did not apply to controls. b
As shown in Table 1, we observed no difference between MS patients and controls either in PvuII and XbaI genotypes or in allele frequencies. As indicated in Table 2, the presence of the XbaI polymorphism in MS patients was not associated with a higher risk of acquiring MS. The finding did not change after stratification for age and clinical course. Table 3 indicates that the PvuII polymorphism did not influence the risk of developing MS. Also in this case, when we analyzed the risk stratifying by age at onset of MS and clinical course of the disease, again we found no significant association. Nor was any significant difference observed stratifying by sex in either polymorphism. In this paper we failed to show an association between two different polymorphisms of the ESR1 gene and MS. In contrast, a positive association between the P allele of the PvuII polymorphism and MS was observed by Niino et al. [12]. In addition, the same authors found that the XbaI polymorphism might be associated with age at onset of MS. More recently, Mattila et al. [11] demonstrated that women with MS carrying the pp genotype of the ESR1 PvuII polymorphism in combination with HLA-DR2 had an increased risk of MS, suggesting that an interaction between ESR1 and HLADR2 could contribute to the development of MS in women. Taken together, these findings indicate an association between ESR1 gene polymorphisms and MS. However, a completely different result was revealed by our experiments. Such a dissimilarity of results is not by chance when the association between a pathological condition and gene polymorphisms is investigated [14]. This occurrence may depend on the selection criteria for the disease or bias in the selection of controls, but often it depends on the ethnic heterogeneity of the population under study. In comparing our study with those of Niino et al. [12] and Mattila et al. [11], it is worth noting that the three separate investigations were carried out in three populations of different ethnic origin. In the first case the study was conducted in a Japanese population, the second investigation involved people from Finland, whereas the population of our study was from southern Italy. The current
results further suggest that the association between a given disease and a genomic feature may be specific for an ethnically homogeneous population and diverse for populations of different origin. [1] Abramsky, O., Pregnancy and multiple sclerosis, Ann. Neurol., 36 (1994) S38–S41. [2] Becherini, L., Gennari, L., Masi, L., Mansani, L., Massart, F., Morelli, A., Falchetti, A., Gonnelli, S., Fiorelli, G., Tanini, A. and Brandi, M.L., Evidence of a linkage disequilibrium between polymorphisms in the human estrogen receptor alpha-gene and their relationship to bone mass variation in postmenopausal women, Hum. Mol. Genet., 13 (2000) 2043–2050. [3] Compston, A., Genetic susceptibility to multiple sclerosis, In A. Compston, G.Ebers, H. Lassmann, I. McDonald, B. Matthews and H. Wekerle (Eds.), McAlpine’s Multiple Sclerosis, Churchill Livingston, London, 1998, p. 105. [4] Confavreux, C., Hutchinson, M., Hours, M.M., CortinovisTourniaire, P. and Moreau, T., Rate of pregnancy-related relapse in multiple sclerosis, N. Engl. J. Med., 339 (1998) 285–291. [5] Ebers, G., Natural history of multiple sclerosis, In A. Compston, G.Ebers, H. Lassmann, I. McDonald, B. Matthews and H. Wekerle (Eds.), McAlpine’s Multiple Sclerosis, Churchill Livingston, London, 1998, p. 206. [6] Green, S., Walter, P., Kumar, V., Krust, A., Bornert, J.M., Argos, P. and Chambon, P., Human oestrogen receptor cDNA: sequence, expression and homology to v-erb-A, Nature, 320 (1986) 134–139. [7] Jansson, L., Olsson, T. and Holmdahl, R., Estrogen induces a potent suppression of experimental autoimmune encephalomyelitis and collagen-induced arthritis in mice, J. Neuroimmunol., 53 (1994) 203–207. [8] Kim, S., Liva, S.M., Dalal, M.A., Verity, M.A. and Voskuhl, R.R., Estriol ameliorates autoimmune demyelinating disease. Implications for multiple sclerosis, Neurology, 52 (1999) 1230–1238. [9] Kobayashi, S., Inoue, S., Hosoi, Y., Shiraki, M. and Orimo, H., Association of bone mineral density with polymorphism of the estrogen receptor gene, J. Bone Miner. Res., 11 (1996) 306–311. [10] Kulper, G.G., Enmark, E., Pelto-Huikko, M., Nilsson, S. and Gustafsson, J.A., Cloning of a novel receptor expressed in rat prostate and ovary, Proc. Natl. Acad. Sci. USA, 93 (1996) 5925–5930. [11] Mattila, K.M., Luomala, M., Lehtima¨ ki, T., Laippala, P.,
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Koivula, T. and Elovaara, I., Interaction between ESRI and HLA-DR2 may contribute to the development of MS in women, Neurology, 56 (2001) 1246–1247. [12] Niino, M., Kiruchi, S., Fukazawa, T., Yabe, I. and Tashiro, K., Estrogen receptor gene polymorphism in Japanese patients with multiple sclerosis, J. Neurol. Sci., 179 (2000) 70–75.
[13] Poser, C.M., Paty, D.W., Scheinberg, L., McDonald, W.I., Davis, F.A., Ebers, G.C., Johnson, K.P., Sibley, W.A., Silberberg, D.H. and Tourtellotte, W.W., New diagnostic criteria for multiple sclerosis: guidelines for research protocols, Ann. Neurol., 13 (1983) 227–231. [14] Weinshenker, B.G. and Kanrtarcy, O.H., Seeking genes for MS. Big risks for big gains, Neurology, 54 (2000) 542–544.
Lack of association between estrogen receptor 1 gene polymorphisms and multiple sclerosis in southern Italy in humans Giovanni Savettieri a, Rita Cittadella b, Paola Valentino c, Ida Manna b, Virginia Andreoli b, Antonella La Russa b, Gaetana La Porta b, Francesca Ruscica c, Paolo Ragonese a, Domenico Pirritano c, Simona Bonavita d, Gioacchino Tedeschi d, Aldo Quattrone b,c,* a Institute of Neurology, University of Palermo, Palermo, Italy Institute of Neurological Sciences, National Research Council, Mangone (Cosenza), Italy c Institute of Neurology, Policlinico Mater Domini, University Magna Graecia, Catanzaro, Italy d 2nd Department of Neurology, 2nd University of Naples, Naples, Italy b
Received 8 October 2001; received in revised form 5 April 2002; accepted 11 April 2002
Abstract Estrogen receptor 1 gene polymorphisms (ESR1) have been found to be associated with multiple sclerosis (MS) in both Japanese and Finnish populations. We investigated the association between ESR1 polymorphisms (PvuII and XbaI) and MS in a study of 132 MS patients and 129 controls from the same geographic background (southern Italy). Allelic and genotypic frequencies were not different between MS patients and population controls for either the PvuII or XbaI polymorphism. This result suggests that the association between a given disease and a genomic characteristic must be confirmed by separate investigations in different populations. q 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Multiple sclerosis; Estrogen receptor; Polymorphism; Italians; Genetic susceptibility
There are many reasons to suppose that sexual hormones may play a role in multiple sclerosis (MS): the frequency of MS is higher in women [3]; MS onset occurs more frequently during the reproductive years [5]; and the period of gestation is considered at low risk for relapse in women affected by MS [4]. On the contrary, however, the puerperium is considered at high risk [1,4]. Studies have shown that estrogens are able to inhibit the progression of experimental allergic encephalomyelitis (EAE), i.e. the experimental model of MS [7]. In addition, estriol treatment reduces the severity of EAE [8]. Estrogens act through interaction with nuclear receptors, and previous studies have determined the structure of the estrogen receptor 1 gene (ESR1) [6,10]. A positive association between ESR1 and MS has been recently reported. Niino et al. [12] have shown an association between the ESR1 PvuII polymorphism and a higher susceptibility in Japanese patients to acquiring MS, and Mattila et al. [11] suggested an association between the pp genotype of the * Corresponding author. Tel.: 139-961-775-322; fax: 139-961777-775. E-mail address: [email protected] (A. Quattrone).
PvuII polymorphism of the ESR1 gene and the human leukocyte antigen (HLA)-DR2 with MS. In our study we investigated the association between ESR1 gene polymorphisms and MS to verify whether or not the association found in both the Japanese and Finnish MS patients was confirmed in an ethnically different population. Blood was collected from 132 MS patients (51 men and 81 women) and 129 healthy controls (63 men and 66 women). Patients with MS were consecutively selected among the outpatients attending the Institute of Neurology at the University of Catanzaro, Italy. Informed consent was obtained from all patients and healthy controls. Among these individuals, 104 were affected by the relapsing-remitting form, 21 by a secondary progressive form, and seven by a primary progressive form. The median age was 38.5 (range 15–78); the median age at onset of the disease was 25 years (range 15–54). The control group had a median age of 30 years (range 18–48). All patients and controls were born in Calabria and had lived in southern Italy for many generations. Diagnosis of MS was made according to Poser’s criteria [13]. Genomic DNA was extracted from EDTA blood samples
0304-3940/02/$ - see front matter q 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S03 04 - 394 0( 0 2) 00 41 0- X
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G. Savettieri et al. / Neuroscience Letters 327 (2002) 115–118
Table 1 Estrogen receptor 1 polymorphisms in MS patients and controls MS patients (%) Genotype frequencies (PvuII) PP pp Pp Allele frequencies P p Genotype frequencies (XbaI) XX xx Xx Allele frequencies X x
Controls (%)
x2
P
23 (17.4) 42 (31.8) 67 (50.8)
24 (18.6) 34 (26.4) 71 (55.0)
0.01 1.57 0.32
0.93 0.21 0.57
113 (42.8) 151 (57.2)
119 (46.1) 139 (53.9)
0.46 0.46
0.50 0.50
26 (19.7) 40 (30.3) 66 (50.0)
22 (17.1) 35 (27.1) 72 (55.8)
0.15 0.71 0.91
0.70 0.40 0.34
118 (44.7) 146 (55.3)
116 (45.0) 142 (55.0)
by a standard phenol-chloroform extraction procedure. ESR1 gene polymorphisms were determined by PvuII and XbaI restriction endonuclease digestion of polymerase chain reaction (PCR) products, as described by Kobayashi et al. [9]. The PCR products that contained a part of intron 1 and exon 2 of the ESR1 gene were digested for 4 h with PvuII and XbaI (Roche) at 378C, producing fragments of 1300 bp (P allele) or 850 1 450 bp (p allele), and of 1300 bp (X allele) or 900 1 400 bp (x allele), respectively. The presence of the restriction site for each endonuclease was conventionally indicated with a lowercase letter (p or x, respectively, for PvuII and XbaI endonucleases) while an uppercase letter (P or X) indicated the absence of the restriction site. The different alleles of patients and controls were compared by the Chi 2 test and Fisher exact test. The Hardy–Weinberg equilibrium was tested for both polymorphisms by standard x 2 goodness of fit test. The relative risk for each polymorphism was estimated through the
calculation of odds ratio (OR). All ORs were adjusted for sex using logistic regression models. For each OR, a 95% confidence interval (CI) was computed and statistical tests were performed by computing two-sided P values. We estimated that with a difference in frequency of P allele between cases and controls greater than 13% the number of individuals of our sample gave sufficient statistical power (more than 80%) to detect the difference at 0.05 (two-tailed) level. All statistical analyses were performed with SPSS software for Windows 95/98 (version 10.0.7, SPSS, Chicago, IL). The distribution of PvuII and XbaI genotypes in control subjects was very similar to that previously reported in an Italian population [2]. The genotype distribution was in Hardy–Weinberg equilibrium both in controls (PvuII, P ¼ 0:222; XbaI, P ¼ 0:147) and MS subjects (PvuII, P ¼ 0:274; XbaI, P ¼ 0:896). A strong linkage disequilibrium between PvuII and XbaI polymorphisms was detected in MS patients (P , 0:00001, D 0 ¼ 0:86) as well as in controls (P , 0:00001, D 0 ¼ 0:93).
Table 2 Association between MS and XbaI polymorphism Genotype
xx versus XX Xx versus XX xx and Xx versus XX: total sample xx versus Xx and XX: total sample Age at onset #25 years b Age at onset .25 years b a
Genotype frequency Cases (N ¼ 132)
Controls (N ¼ 129)
40/66 66/92 106/132 40/132 54/67 51/64
35/57 72/94 107/129 35/129 94/129 94/129
Odds ratio (CI) a
P value
1.11 (0.83–1.48) 1.57 (0.92–2.70) 0.70 (0.42–1.16) 1.13 (0.74–1.72) 1.25 (0.64–2.43) 0.80 (0.41–1.56)
0.48 0.10 0.17 0.56 0.50 0.50
Odds ratios were adjusted by sex using logistic regression, because cases and controls were not matched by sex. The analysis was made by stratifying cases (xx and Xx versus XX) by median age at onset of MS. Age at onset was unknown in one case. b
G. Savettieri et al. / Neuroscience Letters 327 (2002) 115–118
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Table 3 Association between MS and PvuII polymorphism Genotype
pp versus PP Pp versus PP pp and Pp versus PP: total sample pp versus Pp and PP: total sample Age at onset #25 years b,c Age at onset .25 years a,b
Genotype frequency Cases (N ¼ 132)
Controls (N ¼ 129)
42/65 67/90 109/132 42/132 56/67 52/64
34/58 71/95 105/129 34/129 105/129 105/129
Odds ratio (CI) a
P value
1.30 (0.74–2.27) 0.91 (0.53–1.55) 1.01 (0.61–1.67) 1.27 (0.83–1.94) 1.26 (0.62–2.55) 0.79 (0.39–1.60)
0.36 0.74 0.98 0.26 0.52 0.52
a
Odds ratios were adjusted by sex using logistic regression, because cases and controls were not matched by sex. The analysis was made by stratifying cases (pp or Pp versus PP) by median age at onset of MS. Age at onset was unknown in one case. c Stratification was restricted to cases because the variable did not apply to controls. b
As shown in Table 1, we observed no difference between MS patients and controls either in PvuII and XbaI genotypes or in allele frequencies. As indicated in Table 2, the presence of the XbaI polymorphism in MS patients was not associated with a higher risk of acquiring MS. The finding did not change after stratification for age and clinical course. Table 3 indicates that the PvuII polymorphism did not influence the risk of developing MS. Also in this case, when we analyzed the risk stratifying by age at onset of MS and clinical course of the disease, again we found no significant association. Nor was any significant difference observed stratifying by sex in either polymorphism. In this paper we failed to show an association between two different polymorphisms of the ESR1 gene and MS. In contrast, a positive association between the P allele of the PvuII polymorphism and MS was observed by Niino et al. [12]. In addition, the same authors found that the XbaI polymorphism might be associated with age at onset of MS. More recently, Mattila et al. [11] demonstrated that women with MS carrying the pp genotype of the ESR1 PvuII polymorphism in combination with HLA-DR2 had an increased risk of MS, suggesting that an interaction between ESR1 and HLADR2 could contribute to the development of MS in women. Taken together, these findings indicate an association between ESR1 gene polymorphisms and MS. However, a completely different result was revealed by our experiments. Such a dissimilarity of results is not by chance when the association between a pathological condition and gene polymorphisms is investigated [14]. This occurrence may depend on the selection criteria for the disease or bias in the selection of controls, but often it depends on the ethnic heterogeneity of the population under study. In comparing our study with those of Niino et al. [12] and Mattila et al. [11], it is worth noting that the three separate investigations were carried out in three populations of different ethnic origin. In the first case the study was conducted in a Japanese population, the second investigation involved people from Finland, whereas the population of our study was from southern Italy. The current
results further suggest that the association between a given disease and a genomic feature may be specific for an ethnically homogeneous population and diverse for populations of different origin. [1] Abramsky, O., Pregnancy and multiple sclerosis, Ann. Neurol., 36 (1994) S38–S41. [2] Becherini, L., Gennari, L., Masi, L., Mansani, L., Massart, F., Morelli, A., Falchetti, A., Gonnelli, S., Fiorelli, G., Tanini, A. and Brandi, M.L., Evidence of a linkage disequilibrium between polymorphisms in the human estrogen receptor alpha-gene and their relationship to bone mass variation in postmenopausal women, Hum. Mol. Genet., 13 (2000) 2043–2050. [3] Compston, A., Genetic susceptibility to multiple sclerosis, In A. Compston, G.Ebers, H. Lassmann, I. McDonald, B. Matthews and H. Wekerle (Eds.), McAlpine’s Multiple Sclerosis, Churchill Livingston, London, 1998, p. 105. [4] Confavreux, C., Hutchinson, M., Hours, M.M., CortinovisTourniaire, P. and Moreau, T., Rate of pregnancy-related relapse in multiple sclerosis, N. Engl. J. Med., 339 (1998) 285–291. [5] Ebers, G., Natural history of multiple sclerosis, In A. Compston, G.Ebers, H. Lassmann, I. McDonald, B. Matthews and H. Wekerle (Eds.), McAlpine’s Multiple Sclerosis, Churchill Livingston, London, 1998, p. 206. [6] Green, S., Walter, P., Kumar, V., Krust, A., Bornert, J.M., Argos, P. and Chambon, P., Human oestrogen receptor cDNA: sequence, expression and homology to v-erb-A, Nature, 320 (1986) 134–139. [7] Jansson, L., Olsson, T. and Holmdahl, R., Estrogen induces a potent suppression of experimental autoimmune encephalomyelitis and collagen-induced arthritis in mice, J. Neuroimmunol., 53 (1994) 203–207. [8] Kim, S., Liva, S.M., Dalal, M.A., Verity, M.A. and Voskuhl, R.R., Estriol ameliorates autoimmune demyelinating disease. Implications for multiple sclerosis, Neurology, 52 (1999) 1230–1238. [9] Kobayashi, S., Inoue, S., Hosoi, Y., Shiraki, M. and Orimo, H., Association of bone mineral density with polymorphism of the estrogen receptor gene, J. Bone Miner. Res., 11 (1996) 306–311. [10] Kulper, G.G., Enmark, E., Pelto-Huikko, M., Nilsson, S. and Gustafsson, J.A., Cloning of a novel receptor expressed in rat prostate and ovary, Proc. Natl. Acad. Sci. USA, 93 (1996) 5925–5930. [11] Mattila, K.M., Luomala, M., Lehtima¨ ki, T., Laippala, P.,
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G. Savettieri et al. / Neuroscience Letters 327 (2002) 115–118
Koivula, T. and Elovaara, I., Interaction between ESRI and HLA-DR2 may contribute to the development of MS in women, Neurology, 56 (2001) 1246–1247. [12] Niino, M., Kiruchi, S., Fukazawa, T., Yabe, I. and Tashiro, K., Estrogen receptor gene polymorphism in Japanese patients with multiple sclerosis, J. Neurol. Sci., 179 (2000) 70–75.
[13] Poser, C.M., Paty, D.W., Scheinberg, L., McDonald, W.I., Davis, F.A., Ebers, G.C., Johnson, K.P., Sibley, W.A., Silberberg, D.H. and Tourtellotte, W.W., New diagnostic criteria for multiple sclerosis: guidelines for research protocols, Ann. Neurol., 13 (1983) 227–231. [14] Weinshenker, B.G. and Kanrtarcy, O.H., Seeking genes for MS. Big risks for big gains, Neurology, 54 (2000) 542–544.