Genetic polymorphisms and their effects on the severity of silicosis in workers exposed to silica in Brazil.

OBJECTIVE: Silicosis is a pneumoconiosis characterized by fibrosis of the lung parenchyma caused by inhalation of silica particles. Genetic factors might play a role in the severity silicosis. We sought to evaluate the influence of polymorphisms in the ACE, FAS, FASLG, NOS2, IL1RN, FAM13A, TGFB1, and TNF genes on the severity of silicosis. METHODS: Nine polymorphisms were genotyped by PCR in a sample of 143 patients with silicosis in the state of Rio de Janeiro, Brazil. RESULTS: Fifty-seven patients (40%) were classified as having simple silicosis and 86 (60%) were classified as having complicated silicosis. The TT genotype of rs1800469 in the TGFB1 gene showed a protective effect for complicated silicosis (OR = 0.35; 95% CI, 0.14-0.92; p = 0.028) when compared with the other two genotypes (CC+CT). The polymorphic T allele of rs763110 in the FASLG gene (OR = 0.56; 95% CI, 0.31-0.99; p = 0.047), as well as a dominant model for the T allele (TT+CT: OR = 0.37; 95% CI, 0.15-0.96; p = 0.037), also showed a protective effect. When patients with simple silicosis despite having been exposed to silica for a longer time (> 44,229 hours) were compared with patients with complicated silicosis despite having been exposed to silica for a shorter time, the T allele of rs763110 in the FASLG gene (OR = 0.20; 95% CI, 0.08-0.48; p < 0.0001), as well as dominant and recessive models (OR = 0.06; 95% CI, 0.00-0.49; p = 0.01 and OR = 0.22; 95% CI, 0.06-0.77; p = 0.014, respectively), showed a protective effect against the severity of silicosis. CONCLUSIONS: It appears that rs1800469 polymorphisms in the TGFB1 gene and rs763110 polymorphisms in the FASLG gene are involved in the severity of silicosis. Given the lack of studies relating genetic polymorphisms to the severity of silicosis, these results should be replicated in other populations.

Genetic polymorphisms and their effects on the severity of silicosis in workers exposed to silica in Brazil / Polimorfismos genéticos e seus efeitos na gravidade da silicose em trabalhadores expostos à sílica no Brasil

ABSTRACT Objective: Silicosis is a pneumoconiosis characterized by fibrosis of the lung parenchyma caused by inhalation of silica particles. Genetic factors might play a role in the severity silicosis. We sought to evaluate the influence of polymorphisms in the ACE, FAS, FASLG, NOS2, IL1RN, FAM13A, TGFB1, and TNF genes on the severity of silicosis. Methods: Nine polymorphisms were genotyped by PCR in a sample of 143 patients with silicosis in the state of Rio de Janeiro, Brazil. Results: Fifty-seven patients (40%) were classified as having simple silicosis and 86 (60%) were classified as having complicated silicosis. The TT genotype of rs1800469 in the TGFB1 gene showed a protective effect for complicated silicosis (OR = 0.35; 95% CI, 0.14-0.92; p = 0.028) when compared with the other two genotypes (CC+CT). The polymorphic T allele of rs763110 in the FASLG gene (OR = 0.56; 95% CI, 0.31-0.99; p = 0.047), as well as a dominant model for the T allele (TT+CT: OR = 0.37; 95% CI, 0.15-0.96; p = 0.037), also showed a protective effect. When patients with simple silicosis despite having been exposed to silica for a longer time (> 44,229 hours) were compared with patients with complicated silicosis despite having been exposed to silica for a shorter time, the T allele of rs763110 in the FASLG gene (OR = 0.20; 95% CI, 0.08-0.48; p < 0.0001), as well as dominant and recessive models (OR = 0.06; 95% CI, 0.00-0.49; p = 0.01 and OR = 0.22; 95% CI, 0.06-0.77; p = 0.014, respectively), showed a protective effect against the severity of silicosis. Conclusions: It appears that rs1800469 polymorphisms in the TGFB1 gene and rs763110 polymorphisms in the FASLG gene are involved in the severity of silicosis. Given the lack of studies relating genetic polymorphisms to the severity of silicosis, these results should be replicated in other populations.

RESUMO Objetivo: A silicose é uma pneumoconiose caracterizada por fibrose do parênquima pulmonar causada por inalação de partículas de sílica. Fatores genéticos podem desempenhar um papel na gravidade da silicose. Nosso objetivo foi avaliar a influência de polimorfismos dos genes ACE, FAS, FASLG, NOS2, IL1RN, FAM13A, TGFB1 e TNF na gravidade da silicose. Métodos: Nove polimorfismos foram genotipados por meio de PCR em uma amostra composta por 143 pacientes com silicose no estado do Rio de Janeiro, Brasil. Resultados: A silicose foi classificada em simples em 57 (40%) dos pacientes e em complicada, em 86 (60%). O genótipo TT do polimorfismo rs1800469 do gene TGFB1 teve efeito protetor contra a silicose complicada (OR = 0,35; IC95%: 0,14-0,92; p = 0,028) em comparação com os outros dois genótipos (CC+CT). O alelo T polimórfico do polimorfismo rs763110 do gene FASLG (OR = 0,56; IC95%: 0,31-0,99; p = 0,047) e um modelo dominante do alelo T (TT+CT: OR = 0,37; IC95%: 0,15-0,96; p = 0,037) também tiveram efeito protetor. Quando se compararam os pacientes que tinham silicose simples com um tempo maior de exposição à sílica (> 44.229 horas) àqueles que tinham silicose complicada com um tempo menor de exposição à sílica, o alelo T do polimorfismo rs763110 do gene FASLG (OR = 0,20; IC95%: 0,08-0,48; p < 0,0001) e modelos dominantes e recessivos (OR = 0,06; IC95%: 0,00-0,49; p = 0,01 e OR = 0,22; IC95%: 0,06-0,77; p = 0,014, respectivamente) tiveram efeito protetor contra a gravidade da silicose. Conclusões: Polimorfismos rs1800469 do gene TGFB1 e polimorfismos rs763110 do gene FASLG parecem estar envolvidos na gravidade da silicose. Como há poucos estudos que tenham estabelecido relações entre polimorfismos genéticos e a gravidade da silicose, esses resultados devem ser replicados em outras populações.

When Leptin Is Not There: A Review of What Nonsyndromic Monogenic Obesity Cases Tell Us and the Benefits of Exogenous Leptin.

Obesity is a pandemic condition of complex etiology, resulting from the increasing exposition to obesogenic environmental factors combined with genetic susceptibility. In the past two decades, advances in genetic research identified variants of the leptin-melanocortin pathway coding for genes, which are related to the potentiation of satiety and hunger, immune system, and fertility. Here, we review cases of congenital leptin deficiency and the possible beneficial effects of leptin replacement therapy. In summary, the cases presented here show clinical phenotypes of disrupted bodily energy homeostasis, biochemical and hormonal disorders, and abnormal immune response. Some phenotypes can be partially reversed by exogenous administration of leptin. With this review, we aim to contribute to the understanding of leptin gene mutations as targets for obesity diagnostics and treatment strategies.

Identification of a Rare and Potential Pathogenic MC4R Variant in a Brazilian Patient With Adulthood-Onset Severe Obesity.

BACKGROUND: The melanocortinergic pathway orchestrates the energy homeostasis and impairments in this system often lead to an increase in body weight. Rare variants in the melanocortin 4 receptor (MC4R) gene resulting in partial or complete loss of function have been described with autosomal co-dominant inheritance. These mutations are the most common cause of non-syndromic monogenic obesity. In this context, this study aimed to sequence the MC4R gene in a Brazilian cohort of adults with severe obesity. METHODS: This study included 163 unrelated probands with Body Mass Index (BMI) ≥ 35 kg/m2, stratified into three groups, according to the period of obesity onset. From the total sample, 25 patients were enrolled in the childhood-onset group (0-11 years), 19 patients in the adolescence/youth-onset group (12-21 years), and 119 patients in the adult-onset group (>21 years). Blood pressure, anthropometric and biochemical characteristics were obtained, and the MC4R coding region of each subject's DNA was assessed using automated Sanger sequencing. RESULTS: Significant anthropometric differences between the groups were observed. Higher body weight and BMI medians were found in patients with childhood-onset or adolescence/youth-onset when compared to the adulthood-onset obesity group. A total of five mutations were identified, including four missense variants: p.Ser36Thr, p.Val103Ile, p.Ala175Thr, and p.Ile251Leu. Additionally, we observed one synonymous variant (p.Ile198=). The p.Ala175Thr variant was identified in a female case with severe obesity and adulthood-onset. This variant was previously described as a partial loss-of-function mutation, in which the minor allele poses dominant-negative effect, probably resulting in reduced cAMP activity. CONCLUSION: This study showed a prevalence of common and rare variants in a cohort of Brazilian adults with severe obesity and candidates to bariatric surgery. We have identified a rare potentially pathogenic MC4R variant in a Brazilian patient with severe and adulthood-onset obesity.

Is individual genetic susceptibility a link between silica exposure and development or severity of silicosis? A systematic review.

BACKGROUND: Silicosis is a lung disease of fibrotic nature resulting from the inhalation and deposition of dust containing crystalline silica. Subjects exposed to the same environmental factors may show distinct radiological manifestations, and since silicosis is known as a multifactorial disease, it is plausible that individual genetic susceptibility may play a role in the pathology. This review of the literature aims to provide an assessment of the present data on the genetic association studies in silicosis and describe the genes that potentially might influence silicosis susceptibility in silica-exposed individuals. METHODS: We accessed the database of PubMed for articles published in English about interindividual genetic susceptibility to silicosis using terms related to the subject matter. RESULTS: Following the evaluation process, 28 studies were included in this systematic review, including 23 original studies and 5 meta-analyses. CONCLUSIONS: Regardless of the advances in the knowledge of the importance of gene variations in silicosis, more studies need to be performed, in particular, special polygenic and genome-wide investigations.

Interleukin 1α and 1ß gene variations are associated with tuberculosis in silica exposed subjects.

INTRODUCTION: Silicosis is a fibrotic lung disease resulting from the inhalation of crystalline silica and can be classified as simple or complicated according to the International Labour Organization criteria. Furthermore, individuals exposed to crystalline silica also have a higher risk for the development of tuberculosis (Tb). The contribution of inflammatory cytokines to the risk of silicosis and Tb in different populations has previously been reported. Since genetic background might be related to susceptibility to silicosis and Tb, the study of polymorphisms within IL-1α, IL-1ß, and tumor necrosis factor protein-coding genes may contribute to elucidating the genetic basis of these diseases. METHODS: Single nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction using restriction fragment length polymorphism or by Taqman methodology, in a sample of 102 silica-exposed patients from Brazil. RESULTS: No significant associations were observed between the SNPs studied and the severity of silicosis. However, significant associations were found between Tb and the C allele (odds ratio [OR] = 1.93, 95% confidence interval [CI], 1.01-3.73) and the CC genotype (OR = 2.34, 95% CI, 1.04-5.31) of IL1A -899C>T. The IL1B +3954C>T polymorphism also showed an association with Tb (T allele dominant model OR = 2.38, 95% CI, 1.04-5.41). CONCLUSION: These preliminary results demonstrate that the IL1A and IL1B gene variations may contribute to some extent to susceptibility to Tb, but not silicosis. However, additional studies are still needed to confirm these results.

OLIG2 gene polymorphisms are associated with nasty, unpleasant and uncontrollable thoughts in obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is one of 10 major debilitating neuropsychiatric disorders, according to the World Health Organization (WHO), affecting around 2.3% of people worldwide. Obsessive-compulsive symptoms are caused by shared or distinct genetic or environmental influences. Several imaging studies have detected white-matter alterations in OCD, and recent studies have demonstrated thatOCD is associated with variations in the OLIG2 gene. The aim of this study was to investigate whether OLIG2 gene is associated with OCD and its clinical features in a Brazilian sample. We genotyped three variants in OLIG2 gene, rs762178, rs1059004, and rs9653711 in 205 OCD patients and 202 healthy controls by Taqman® methodology. Genotypes and alleles distributions were analyzed by χ2 or Fisher exact tests. The rs762178 and rs9653711 polymorphisms were significantly associated with OCD (P = 0.048 and 0.029, respectively). We also observed an association of rs1059004 and rs9653711 with the presence of Obsessive-Compulsive Inventory-Revised (OCI-R) obsessing (unacceptable thoughts) subscore (P = 0.031 and 0.034, respectively). Moreover, the pair of loci consisting of rs762178 and rs9653711 A-G haplotype was associated with OCD (P < 0.0001). The OLIG2 gene may be involved in OCD, particularly in patients showing nasty, unpleasant and uncontrollable thoughts. However, more studies in larger samples are needed to replicate these findings.