Vitiligo in Children: A Better Understanding of the Disease

Identification of TNF-α as Major Susceptible Risk Locus for Vitiligo: A Systematic Review and Meta-Analysis Study in the Asian Population

INTRODUCTION

Vitiligo is a common depigmentation disorder characterized by defined white patches on the skin and affecting around 0.5% to 2% of the general population. Genetic association studies have identified several pre-disposing genes and single nucleotide polymorphisms (SNPs) for vitiligo pathogenesis; nonetheless, the reports are often conflicting and rarely conclusive. This comprehensive meta-analysis study was designed to evaluate the effect of the risk variants on vitiligo aetiology and covariate stratified vitiligo risk in the Asian population, considering all the studies published so far.

METHODS

We followed a systematic and comprehensive search to identify the relevant vitiligo-related candidate gene association studies in PubMed using specific keywords. After data extraction, we calculated, for the variants involved, the study-level unadjusted odds ratio, standard errors, and 95% confidence intervals by using logistic regression with additive, dominant effect, and recessive models using R software package (R, 3.4.2) "metafor." Subgroup analysis was performed using logistic regression (generalized linear model; "glm") of disease status on subgroup-specific genotype counts. For a better understanding of the likely biological function of vitiligo-associated variant obtained through the meta-analysis, in silico functional analyses, through standard publicly available web tools, were also conducted.

RESULTS

Thirty-one vitiligo-associated case-control studies on eleven SNPs were analysed in our study. In the fixed-effect meta-analysis, one variant upstream of TNF-α gene: rs1800629 was found to be associated with vitiligo risk in the additive (p = 4.26E-06), dominant (p = 1.65E-7), and recessive (p = 0.000453) models. After Benjamini-Hochberg false discovery rate (FDR) correction, rs1800629/TNF-α was found to be significant at 5% FDR in the dominant (padj = 1.82E-6) and recessive models (padj = 0.0049). In silico characterization revealed the prioritized variant to be regulatory in nature and thus having potential to contribute towards vitiligo pathogenesis.

CONCLUSION

Our study constitutes the first comprehensive meta-analysis of candidate gene-based association studies reported in the whole of the Asian population, followed by an in silico analysis of the vitiligo-associated variant. According to the findings of our study, TNF-α single nucleotide variant rs1800629G>A has a risk association, potentially contributing to vitiligo pathogenesis in the Asian population.

Evaluation of IL-38, a Newly-introduced Cytokine, in Sera of Vitiligo Patients and Its Relation to Clinical Features

INTRODUCTION

Vitiligo is thought to be an autoimmune disorder caused by melanocytes dysfunction and depigmentation. Among different executors of the immune system in developing the disease, the role of various cytokines has been defined.

OBJECTIVES

We have focused on IL-38, the tenth member of IL-1 cytokine family with a proposed anti-inflammatory role, which has not hitherto been introduced as an anti-inflammatory factor in vitiligo.

METHODS

Sixty-nine generalized vitiligo patients and 72-year-old- and sex-matched healthy individuals were included in this study. IL-38 level was evaluated in sera of all participants using ELISA assay. The relation of IL-38 level to patients characteristics was evaluated.

RESULTS

IL-38 serum level in vitiligo patients (159.5±39.7 pg/ml) was lower than the healthy controls (166.7±34.8pg/ml) (P = 0.039). A weak negative correlation between the age of male patients and their IL-38 serum levels was identified (r = 0.38, P = 0.058). Evaluation of the IL-38 serum levels relationship with patients clinical characteristics showed no correlation with disease onset, stage of depigmentation, and disease activity status.

CONCLUSIONS

The lower levels of IL-38 as an anti-inflammatory cytokine support the inflammatory nature of vitiligo. It indicates the difference of IL-38 in sera of vitiligo patients and healthy controls, as the first report of the lower level of this cytokine in the context of vitiligo. The reason of this difference remains to be clarified; as there are not sufficient study reports revealing the role of gender, ethnicity and inflammation on the cytokine network in the context of vitiligo.

A comprehensive meta-analysis and prioritization study to identify vitiligo associated coding and non-coding SNV candidates using web-based bioinformatics tools

Vitiligo is a prevalent depigmentation disorder affecting around 1% of the general population. So far, various Genome Wide Association Studies (GWAS) and Candidate Gene Association Studies (CGAS) have identified several single nucleotide variants (SNVs) as a risk factor for vitiligo. Nonetheless, little has been discerned regarding their direct functional significance to the disease pathogenesis. In this study, we did extensive data mining and downstream analysis using several experimentally validated datasets like GTEx Portal and web tools like rSNPBase, RegulomeDB, HaploReg and STRING to prioritize 13 SNVs from a set of 291SNVs that have been previously reported to be associated with vitiligo. We also prioritized their underlying/target genes and tried annotating their functional contribution to vitiligo pathogenesis. Our analysis revealed genes like FGFR10P, SUOX, CDK5RAP1 and RERE that have never been implicated in vitiligo previously to have strong potentials to contribute to the disease pathogenesis. The study is the first of its kind to prioritize and functionally annotate vitiligo-associated GWAS and CGAS SNVs and their underlying/target genes, based on functional data available in the public domain database.

Clinical efficacy analysis of 110 cases of childhood vitiligo with non-surgical combined therapy

BACKGROUND

Vitiligo has a negative effect on children's physical and psychological health. Few studies have examined long-term treatment efficacy for childhood vitiligo. Therefore, we evaluated the long-term effectiveness of non-surgical combination therapy in pediatric patients with vitiligo and analyzed factors that affect its efficacy.

METHODS

Pediatric patients (⩽12 years) with vitiligo who were treated with topical corticosteroids/topical calcineurin inhibitors and phototherapy for 12 months were retrospectively studied. Short-term systemic corticosteroids were administered according to individual clinical conditions. All lesions were photographed to assess repigmentation at 3-month intervals. Clinical data, the treatment effectiveness, and factors affecting the therapeutic effect were analyzed.

RESULTS

Overall, 110 children (51 [53.6%] girls; mean [SD] age, 7.1 ± 3.0 years; 104 [94.5%] with activity status) were treated for a mean period of 23.13 ± 14.03 months (range, 5-86 months). The overall >50% repigmentation rate was 64.5%. A longer duration of treatment was associated with a higher repigmentation rate (X² _trend = 36.229, P < .001). The vitiligo disease activity score at the first visit was positively correlated with the overall repigmentation rate (r_s = 0.301, P = .001).

CONCLUSIONS

Treatment lasting longer than 1 year is recommended in children with vitiligo. The best repigmentation effect can be achieved by combination therapy in the rapid progression stage.

Nuclear Factor Erythroid-2-related Factor 2 Gene Polymorphisms in Vitiligo

BACKGROUND

Oxidative stress is now one of the accepted theories of vitiligo development. Nuclear factor erythroid-2-related factor 2 (Nrf2) regulates the expression of antioxidant proteins.

OBJECTIVE

This work aimed to evaluate the association of Nrf2 gene polymorphisms with the susceptibility to vitiligo among a sample of Egyptian patients with vitiligo.

METHODS

This case-control study included 100 patients with vitiligo and 50 healthy matched volunteers serving as a control group. Genotyping was carried out by real-time polymerase chain reaction.

RESULTS

The frequencies of TT, CT, and combined (TT+CT) genotypes and the T allele of Nrf2 (rs35652124) were significantly increased in the studied patients with vitiligo relative to the healthy controls (p<0.001, p=0.012, p<0.001 and p<0.001, respectively). There was a nonsignificant difference between patients and controls regarding Nrf2 (rs6721961) genotypes. However, the T allele of Nrf2 (rs6721961) was significantly predominant in the studied patients compared to in the controls (p=0.029). Among the studied criteria, the T allele of Nrf2 (rs6721961) was predominant in patients with a marginal type of repigmentation (p=0.022), while the G allele of the same single-nucleotide polymorphism was associated with a higher body mass index value (p=0.034). One hundred percent of patients with vitiligo with the Nrf2 (rs6721961) GT genotype had a progressive disease course (p=0.015).

CONCLUSION

Nrf2 (-617 T/G) and (-653 T/C) polymorphism might play a role in patient susceptibility to vitiligo and modify the clinical presentation of the disease.

Vitiligo: An Updated Narrative Review

BACKGROUND

Vitiligo is a relatively common acquired pigmentation disorder that can cause significant psychological stress and stigmatism.

OBJECTIVE

This article aims to familiarize physicians with the clinical manifestations, evaluation, diagnosis, and management of vitiligo.

METHODS

A Pubmed search was conducted in Clinical Queries using the key term "vitiligo". The search included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. The search was restricted to English language. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Approximately one quarter of patients with vitiligo have the onset before 10 years of age. Genetic, immunological, neurogenic and environmental factors may have a role to play in the pathogenesis. Vitiligo typically presents as acquired depigmented, well-demarcated macules/patches that appear milk- or chalk-white in color. Lesions tend to increase in number and enlarge centrifugally in size with time. Sites of predilection include the face, followed by the neck, lower limbs, trunk, and upper limbs. The clinical course is generally unpredictable. In children with fair skin, no active treatment is usually necessary other than the use of sunscreens and camouflage cosmetics. If treatment is preferred for cosmesis, topical corticosteroids, topical calcineurin inhibitors, and narrowband ultraviolet B phototherapy are the mainstays of treatment.

CONCLUSION

The therapeutic effect of all the treatment modalities varies considerably from individual to individual. As such, treatment must be individualized. In general, the best treatment response is seen in younger patients, recent disease onset, darker skin types, and head and neck lesions. Topical corticosteroids and calcineurin inhibitors are the treatment choice for those with localized disease. Topical calcineurin inhibitors are generally preferred for lesions on genitalia, intertriginous areas, face, and neck. Narrowband ultraviolet B phototherapy should be considered in patients who have widespread vitiligo or those with localized vitiligo associated with a significant impact on the quality of life who do not respond to treatment with topical corticosteroids and calcineurin inhibitors.

Successful Treatment of Vitiligo Vietnamese Patients with Vitilinex® Herbal Bio-Actives in Combination with Phototherapy

BACKGROUND

Vitiligo is an acquired pigmentary disease, that causes progressive loss of melanocytes, resulting in hypopigmented skin patches. Current treatments aim at stopping the disease progression and achieving repigmentation of the amelanotic areas. Corticosteroids, surgery, topical immunomodulators, total depigmentation of normal pigmented skin and phototherapy are current treatment options for vitiligo although phototherapy remains the treatment of choice. There is no documented evidence that herbal bio-active products may also be effective treatment options for vitiligo.

AIM

This study aimed to investigate the efficacy and safety of Vitilinex® (herbal bio- actives) alone and in combination with UVB narrowband (311 nm) phototherapy, in the treatment of localised stable or active forms of vitiligo.

MATERIAL AND METHODS

Sixty two subjects with mean age 34.5 years (range: 18-58 years) with mild to moderate vitiligo, consisting of 36 females and 26 males were randomly divided into three treatment groups - Group A (13 females, 10 males) treated with Vitilinex® alone; Group B (12 females, 11 males) were treated with Vitilinex® in combination with narrowband UVB (311 nm) phototherapy for 15 seconds, using a handheld lamp and Group C (8 females, 8 males) were treated with nbUVB (311 nm) phototherapy alone, for 15 seconds over a 12-week period.

RESULTS

In Group A, 9 patients (39%) achieved outstanding improvement with a re-pigmentation rate higher than 75%, with 2 patients experiencing total repigmentation. 6 patients (26%) had marked improvement with a repigmentation rate between 50-75% while 5 patients (22%) showed a moderate response between 25-50% re-pigmentation rate. 3 patients (13%) had minimal or no improvement. In Group B, 16 patients (69.5%) achieved outstanding improvement with a re-pigmentation rate higher than 75%, with 12 patients experiencing total re-pigmentation. 4 patients (17.5 %) achieved a marked improvement with a re-pigmentation rate between 50-75%; 2 patients (8.7%) showed a moderate response with a re-pigmentation rate between 25-50%. 1 (4.3%) patient had minimal or no improvement. In Group C, 6 patients (37.5%) achieved a re-pigmentation rate higher than 75%, with 2 patients experiencing total re-pigmentation. 4 patients (25%) achieved marked improvement with a re-pigmentation rate between 50-75% while 3 patients (18.75%) had a re-pigmentation rate between 25-50%. 3 patients (18.75%) had minimal or no improvement.

CONCLUSION

Vitilinex® herbal bio-actives in combination with nbUVB is a more effective treatment option for vitiligo with 87% of the patients achieving a re-pigmentation rate higher than 50%, compared to Vitilinex® alone (65%) or nbUVB alone (62.5%).