Vitiligo is a disorder causing skin depigmentation, in which several factors have been proposed for its pathogenesis: Environmental, genetic and biological aspects of melanocytes, even those of the surrounding keratinocytes. However, the lack of understanding of the mechanisms has complicated the task of predicting the development and progression. The present study used microarray analysis to characterize the transcriptional profile of skin from Vitiligo Vulgaris (VV) patients and the identified transcripts were validated using targeted high‑throughput RNA sequencing in a broader set of patients. For microarrays, mRNA was taken from 20 skin biopsies of 10 patients with VV (pigmented and depigmented skin biopsy of each), and 5 biopsies of healthy subjects matched for age and sex were used as a control. A signature was identified that contains the expression pattern of 722 genes between depigmented vitiligo skin vs. healthy control, 1,108 between the pigmented skin of vitiligo vs. healthy controls and 1,927 between pigmented skin, depigmented vitiligo and healthy controls (P<0.05; false discovery rate, <0.1). When comparing the pigmented and depigmented skin of patients with vitiligo, which reflects the real difference between both skin types, 5 differentially expressed genes were identified and further validated in 45 additional VV patients by RNA sequencing. This analysis showed significantly higher RNA levels of calpain‑3, dopachrome tautomerase, melan‑A and tyrosinase‑related protein‑1 genes. The data revealed that the pigmented skin of vitiligo is already affected at the level of gene expression and that the main differences between pigmented and non‑pigmented skin are explained by the expression of genes associated with pigment metabolism.

Androgenetic alopecia (AGA) or male pattern baldness is the most common form of hair loss in humans. Despite being a very frequent dermatological entity, molecular pathophysiology remains unclear. Several authors relate the presentation of AGA with a premature apoptotic process during the anagen phase and with an inflammatory microenvironment in the hair follicle. We evaluated a panel of 30 genes associated with inflammation and apoptosis in 5 AGA patients by targeted RNA-Seq. WNT7A gene was highly expressed in patients in stages 3V to 5 on the Hamilton-Norwood scale compared to patients with 5A stage. CASP7 and TNF genes were overexpressed in stages 3V and 4 compared to stages 5 and 5A. Overexpression of these genes detected only at early stages of AGA proves the role of WNT pathway, apoptosis, and inflammation in the development of this disorder.

Alopecia areata (AA) is a skin condition in which hair is lost from certain or all areas of the body. This condition has been described as an immune-mediated complex genetic disease, characterized by the presence of lymphocytes that are directed to the hair follicles in the anagen phase. The gene encoding the protein tyrosine phosphatase, non-receptor type 22 (PTPN22), which is exclusively expressed in immune cells, has been considered as a risk factor associated with a number of autoimmune diseases. In AA, the single nucleotide polymorphism, rs2476601, has been identified as a risk factor in several populations. The aim of the present study was to investigate the effect of PTPN22 C1858T inherited genetic polymorphism on the predisposition to severe forms of AA, in a case-control study on individuals. The study included 64 unrelated patients diagnosed with several types of AA, as well as 225 healthy unrelated subjects. The DNA samples were genotyped for PTPN22 C1858T polymorphism using the polymerase chain reaction-restriction fragment length polymorphism technique. Causal associations were determined by χ2 test and their respective odds ratio (OR) was assessed in a 2×2 contingency table. The results demonstrated a significant association of the T allele [P=0.040; OR=3.196; 95% confidence interval (CI), 0.094–10.279] and the CT genotype (P=0.038; OR=3.313; 95% CI, 1.008–10.892) with patchy AA. In conclusion, the results of the present study suggested the possible involvement of the T allele of the PTPN22 C1858T SNP as a genetic risk factor for this type of AA in the population studied.

Vitiligo is characterized by a skin depigmentation disorder resulting from an autoimmune response targeting melanocytes. Within the genetic factors involved in the development of the vitiligo immune response, various genes in the major histocompatibility complex (MHC) and non‑MHC loci have been considered to be risk factors. The PTPN22 gene encodes for a lymphoid protein tyrosine phosphatase, a regulator of the activation and development of T‑cells. The +1858C/T polymorphism has been associated to autoimmune disease susceptibility in different populations and could be implicated in the onset of vitiligo. To assess the possible association between the presence of PTPN22 +1858C/T and vitiligo, 187 patients with vitiligo and 223 control subjects were analyzed in the study. Genomic DNA was isolated using the salting‑out method and samples were subjected to polymerase chain reaction‑restriction fragment length polymorphism in order to detect the PTPN22 +1858C/T polymorphism. Causal associations were determined by χ2 test and their respective odds ratio (OR) was assessed in a 2x2 contingency table. The results showed an association between active vitiligo and the allele T load [P=0.0418; OR, 2.5706; 95% confidence interval (CI), 1.0040‑6.5816], and active vitiligo‑CT genotype (P=0.0389, OR, 2.6548; 95% CI, 1.0191‑6.9156). In conclusion, the present data indicates a possible association between the PTPN22 +1858C/T genotype and a significant susceptibility of developing an active form of vitiligo.

Vitiligo is a skin disease characterized by depigmentation. Its etiopathogenesis is unclear, but it has been associated with autoimmune processes. Gene polymorphisms in the tumor necrosis factor-α (TNF-α) have been associated with several imflammatory diseases. In particular, the -308G/A polymorphism in the gene promoter region has been reported to be associated with increased plasma levels of TNF-α and with an increased risk to develop autoimmune diseases. To date, this polymorphism has not been associated with vitiligo. To assess a possible association between the TNF-α -308G/A and vitiligo vulgaris (VV), 198 vitiligo patients and 395 control subjects were recruited for the study. A complete demographic and clinical profile of each case was registered to analyze the possible risk factors of vitiligo. Genomic DNA isolated from peri­pheral blood was subjected to PCR-RFLP for genotyping of the TNF-α -308G/A polymorphism. Causal associations were determined by χ2 test and their respective OR was assessed in a 2x2 contingency table. When population variables of type of vitiligo, gender, age of disease onset, and active disease status were considered, an association between active VV and the TNF-α GA genotype was found (P=0.0295, OR=2.0; 95% CI 1.01‑3.93). All other variables were irrelevant to vitiligo. Our data suggest a possible association between the TNF-α -308 GA genotype and the active form of VV in a Mexican population.