Elisa Docampo

Deletion of LCE3C and LCE3B is a susceptibility factor for psoriatic arthritis: a study in Spanish and Italian populations and meta-analysis.

OBJECTIVE The LCE3C_LCE3B-del variant is associated with psoriasis and rheumatoid arthritis. Its role in psoriatic arthritis (PsA) is unclear, however, as shown by 3 recent studies with contradictory results. In order to investigate whether LCE3C_LCE3B-del constitutes a risk factor for PsA susceptibility, we first tested this variant in patients with PsA from Spanish and Italian populations and then performed a meta-analysis including the previous case-control studies. METHODS We genotyped LCE3C_LCE3B-del and its tag single-nucleotide polymorphism (SNP), rs4112788, in an original discovery cohort of 424 Italian patients with PsA and 450 unaffected control subjects. A Spanish replication cohort consisting of 225 patients with PsA and 469 control subjects was also genotyped. A meta-analysis considering 7,758 control subjects and 2,325 patients with PsA was also performed. RESULTS We observed a significant association between PsA and the LCE3C_LCE3B-del tag SNP in the Italian and Spanish cohorts, with an overall corrected P value of 0.00019 and a corresponding odds ratio of 1.35 (95% confidence interval 1.14-1.59). Stratified analyses by subphenotype indicated a stronger association for patients with oligoarticular disease. Meta-analysis including data from all previous published studies confirmed an association of PsA with the LCE3C_LCE3B-del tag SNP. CONCLUSION LCE3C_LCE3B-del is a susceptibility factor for PsA, confirming the existence of a shared risk factor involving the epidermal skin barrier in autoimmune disorders.

Cluster analysis of clinical data identifies fibromyalgia subgroups.

Introduction Fibromyalgia (FM) is mainly characterized by widespread pain and multiple accompanying symptoms, which hinder FM assessment and management. In order to reduce FM heterogeneity we classified clinical data into simplified dimensions that were used to define FM subgroups. Material and Methods 48 variables were evaluated in 1,446 Spanish FM cases fulfilling 1990 ACR FM criteria. A partitioning analysis was performed to find groups of variables similar to each other. Similarities between variables were identified and the variables were grouped into dimensions. This was performed in a subset of 559 patients, and cross-validated in the remaining 887 patients. For each sample and dimension, a composite index was obtained based on the weights of the variables included in the dimension. Finally, a clustering procedure was applied to the indexes, resulting in FM subgroups. Results Variables clustered into three independent dimensions: “symptomatology”, “comorbidities” and “clinical scales”. Only the two first dimensions were considered for the construction of FM subgroups. Resulting scores classified FM samples into three subgroups: low symptomatology and comorbidities (Cluster 1), high symptomatology and comorbidities (Cluster 2), and high symptomatology but low comorbidities (Cluster 3), showing differences in measures of disease severity. Conclusions We have identified three subgroups of FM samples in a large cohort of FM by clustering clinical data. Our analysis stresses the importance of family and personal history of FM comorbidities. Also, the resulting patient clusters could indicate different forms of the disease, relevant to future research, and might have an impact on clinical assessment.

Deletion of the late cornified envelope genes, LCE3C and LCE3B, is associated with rheumatoid arthritis.

OBJECTIVE The risk of rheumatoid arthritis (RA) is increased in the offspring of individuals affected with various autoimmune disorders, including psoriasis. Recently, the deletion of 2 genes from the late cornified envelope (LCE) gene cluster, LCE3C and LCE3B, has been associated with psoriasis in several populations. The purpose of this study was to assess whether this polymorphic gene deletion could also be involved in susceptibility to RA. METHODS We tested for association between the LCE3C_LCE3B copy number variant and a single-nucleotide polymorphism in strong linkage disequilibrium with this variant (rs4112788) and RA in 2 independent case-control data sets (197 and 400 samples from patients with RA, respectively, and 411 and 567 samples from control subjects, respectively), collected at 4 Spanish hospitals. All samples were directly typed for presence of the LCE3C_LCE3B deletion (LCE3C_LCE3B-del) by polymerase chain reaction, and association analysis was performed using the SNPassoc R package. RESULTS An association of homozygosity for the LCE3C_LCE3B-del and rs4112788 C allele with the risk of RA was observed in the first data set and was replicated in an independent case-control set. A combined analysis showed an overall P value of 0.0012 (odds ratio [OR] 1.45, 95% confidence interval [95% CI] 1.16-1.81) for association of the LCE3C_LCE3B-del. When the analysis was stratified for serologic data, we observed association in anti-cyclic citrullinated peptide (anti-CCP)-positive patients (P = 0.012, OR 1.51 [95% CI 1.09-2.13]) but not in anti-CCP-negative patients. CONCLUSION We have identified an association between the LCE3C_LCE3B-del and RA, and we have verified a pleiotropic effect of a common genetic risk factor (LCE3C_LCE3B-del) for autoimmune diseases that is involved in both psoriasis and RA.

Genome-wide analysis of single nucleotide polymorphisms and copy number variants in fibromyalgia suggest a role for the central nervous system.

Summary Variants in NRXN3 and MYT1L are associated with fibromyalgia. Our results point to a role for the central nervous system in susceptibility to fibromyalgia. ABSTRACT Fibromyalgia (FM) is a highly disabling syndrome defined by a low pain threshold and a permanent state of pain. The mechanisms explaining this complex disorder remain unclear, and its genetic factors have not yet been identified. With the aim of elucidating FM genetic susceptibility factors, we selected 313 FM cases having low comorbidities, and we genotyped them on the Illumina 1 million duo array. Genotypic data from 220 control women (Illumina 610k array) was obtained for genome‐wide association scan (GWAS) analysis. Copy number variants in FM susceptibility were analyzed by array comparative genomic hybridization (aCGH) experiments on pooled samples using the Agilent 2 × 400K platform. No single nucleotide polymorphism (SNP) reached GWAS association threshold, but 21 of the most associated SNPs were chosen for replication in 952 cases and 644 controls. Four of the SNPs selected for replication showed a nominal association in the joint analysis, and rs11127292 (MYT1L) was found to be associated to FM with low comorbidities (P = 4.28 × 10−5, odds ratio [95% confidence interval] = 0.58 [0.44–0.75]). aCGH detected 5 differentially hybridized regions. They were followed up, and an intronic deletion in NRXN3 was demonstrated to be associated to female cases of FM with low levels of comorbidities (P = .021, odds ratio [95% confidence interval] = 1.46 [1.05–2.04]). Both GWAS and aCGH results point to a role for the central nervous system in FM genetic susceptibility. If the proposed FM candidate genes were further validated in replication studies, this would highlight a neurocognitive involvement in agreement with latest reports.

Association of neurexin 3 polymorphisms with smoking behavior.

The Neurexin 3 gene (NRXN3) has been associated with dependence on various addictive substances, as well as with the degree of smoking in schizophrenic patients and impulsivity among tobacco abusers. To further evaluate the role of NRXN3 in nicotine addiction, we analyzed single nucleotide polymorphisms (SNPs) and a copy number variant (CNV) within the NRXN3 genomic region. An initial study was carried out on 157 smokers and 595 controls, all of Spanish Caucasian origin. Nicotine dependence was assessed using the Fagerström index and the number of cigarettes smoked per day. The 45 NRXN3 SNPs genotyped included all the SNPs previously associated with disease, and a previously described deletion within NRXN3. This analysis was replicated in 276 additional independent smokers and 568 controls. Case–control association analyses were performed at the allele, genotype and haplotype levels. Allelic and genotypic association tests showed that three NRXN3 SNPs were associated with a lower risk of being a smoker. The haplotype analysis showed that one block of 16 Kb, consisting of two of the significant SNPs (rs221473 and rs221497), was also associated with lower risk of being a smoker in both the discovery and the replication cohorts, reaching a higher level of significance when the whole sample was considered [odds ratio = 0.57 (0.42–0.77), permuted P = 0.0075]. By contrast, the NRXN3 CNV was not associated with smoking behavior. Taken together, our results confirm a role for NRXN3 in susceptibility to smoking behavior, and strongly implicate this gene in genetic vulnerability to addictive behaviors.

Screening for the presence of FMR1 premutation alleles in women with fibromyalgia

Fibromyalgia is a chronic condition characterized by widespread pain, fatigue, non-restorative sleep and cognitive difficulties that affects 2-4% of the general population. Recently a possible relationship between the FMR1 premutation and fibromyalgia has been pointed out. In attempt to gather more data we screened for the FMR1 CGG expansion 700 DNA samples from unrelated fibromyalgia patients. This data might be useful for evaluating the incorporation of this test in rheumatologic procedures for women with fibromyalgia. The observed frequency of FMR1 premutation carriers (3 of 700, 0.4%) is not significantly different from the estimated rate in the general female population (1/250-1/400) (P=0.539, P=0.716). Clinical examination of the FMR1 premutation carriers identified revealed that all of them had important neurological symptoms with regard to muscular symptoms, neurocognitive alterations and neurovegetative impairments. With regard to other clinical aspects of the disease the cases apparently did not differ from the average fibromyalgia patients. On the basis of our results an FMR1 screening among fibromyalgia female patients would not be recommended. However it would be worthwhile to further evaluate the different clinical presentations that fibromyalgia patients might present based on their FMR1 premutation carrier status.

Osteonecrosis vertebral y vertebroplastia percutánea

La osteonecrosis vertebral se caracteriza por presentar el fenomeno de vacio intravertebral. Es un proceso poco frecuente y aunque puede ser debido a diferentes afecciones, la causa mas frecuente es la postraumatica. La explicacion de que aparezca gas intravertebral no es del todo conocida. Presentamos el caso de una paciente de 74 anos que despues de sufrir un traumatismo vertebral inicio clinica de dolor dorsolumbar intenso. El estudio radiologico simple, la tomografia computarizada y la resonancia magnetica confirmaron el fenomeno del vacio intravertebral. Hemos hecho una revision de este signo radiologico y comentamos la evolucion despues de vertebroplastia percutanea.Vertebral osteonecrosis is characterized by the presence of the intravertebral vacuum phenomenon. It is a relatively uncommon disease and although it may be caused by different pathologies, the most frequent cause is posttraumatic. The explanation for the presence of intravertebral gas is not known completely. We present the case of a 74-year-old patient who after suffering a vertebral traumatism, to complain of intense vertebral pain. A simple radiological study, CT scan, and magnetic resonance confirmed the presence of intravertebral vacuum phenomenon. We studied this radiological sign and then commented on its evolution after percutaneous vertebroplasty.

Eficacia de la gabapentina en el tratamiento del síndrome del túnel carpiano

BACKGROUND AND OBJECTIVE: To evaluate the analgesic efficacy and safety of gabapentin in the treatment of carpal tunnel syndrome (CTS), as well as the electromyographic (EMG) evolution after 6 months. PATIENTS AND METHOD: A prospective study with a 6-month follow-up of patients with EMG diagnosis of primary CTS starting treatment with 1.800 mg/day of gabapentin. At baseline visit and after 6 months of treatment a complete clinical evaluation and an EMG study were performed. Adverse effects of gabapentin were also registered. RESULTS: Twenty-five patients were included, mean age (standard deviation) 58.88 (7.69) years. After 6 months of treatment, a statistically significant reduction of pain (p = 0.001) and improvement of severity of symptoms (p = 0.008) were observed, although functional capacity did not change. EMG was performed in 19 patients at 6 months. Compared to baseline EMG: 52.6% patients showed no changes in EMG findings, while 5.3% patients showed improvement and in 26.3% the EMG was normal. Progression was only seen in 15.8% of patients after 6 months of treatment. In 28% of the patients gabapentin was stopped because of side effects. CONCLUSIONS: In our series, gabapentin was effective in the reduction of pain and improvement of the severity of the symptoms. Results of EMG after 6 months of treatment showed no changes, with improvement and/or remission in 84.2% of the cases. The drug was safe and well tolerated.

Vertebral Osteonecrosis and Percutaneous Vertebroplasty

Vertebral osteonecrosis is characterized by the presence of the intravertebral vacuum phenomenon. It is a relatively uncommon disease and although it may be caused by different pathologies, the most frequent cause is posttraumatic. The explanation for the presence of intravertebral gas is not known completely. We present the case of a 74-year-old patient who after suffering a vertebral traumatism, to complain of intense vertebral pain. A simple radiological study, CT scan, and magnetic resonance confirmed the presence of intravertebral vacuum phenomenon. We studied this radiological sign and then commented on its evolution after percutaneous vertebroplasty.