Vitamin D receptor gene polymorphisms are not associated with alopecia areata

Pediatric Alopecia Areata

BACKGROUND

Alopecia areata (AA) is a non-scarring hair loss disorder of autoimmune etiology.

OBJECTIVE

To familiarize physicians with the clinical presentation, diagnosis, evaluation, and management of pediatric alopecia areata.

METHODS

The search term "Alopecia areata" was entered into a Pubmed search. A narrow scope was applied to the categories of "epidemiology", "clinical diagnosis", "investigations", "comorbidities", and "treatment". Meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews were included. Only papers published in the English language were included. A descriptive, narrative synthesis was provided of the retrieved articles.

RESULTS

AA is an autoimmune disease of unknown etiology. It is the third most common dermatologic presentation in children with a lifetime risk of 1-2%. Diagnosing AA can be made on the basis of the history and clinical findings. Patients will often present with patchy, non-scarring hair loss, generally affecting the scalp. History may reveal a personal or family medical history of autoimmune or atopic disease or a recent stressful event. Tricoscopic examination will classically show "exclamation point hairs" and "yellow dots". Nonspecific nail changes may be present. Other clinical variants include alopecia totalis, alopecia universalis, ophiasis, sisaipho, and Canitis subita. There are multiple treatment options for AA, including conservative treatment, and topical, oral, and injectable medications.

CONCLUSION

AA is an autoimmune disease with a heterogeneous presentation and unpredictable clinical course. Although there is no cure for AA, there are many current treatment options available to help manage this disfiguring disease.

Combined Diet and Supplementation Therapy Resolves Alopecia Areata in a Paediatric Patient: A Case Study

Alopecia areata (AA) is a common autoimmune condition resulting in spot baldness and, rarely, more extensive hair loss. There is an association between both the incidence and the severity of AA and several micronutrients, including vitamin D and zinc. This case reports an eight-year-old male diagnosed with AA and treated with a diet and supplemental regimen based on unrefined foods, rich in vitamins A and D, zinc, and supplemented with a multi-nutrient, zinc sulfate, and fish oil with vitamin D. Complete remission of AA was achieved within five months.

Vitamin D Receptor Gene Polymorphisms Taq-1 and Cdx-1 in Female Pattern Hair Loss

Background

Female pattern hair loss (FPHL) is an important cause of hair loss in adult women and has a major impact on patient's quality of life. It evolves from the progressive miniaturization of follicles that leads to a subsequent decrease of hair density, leading to non-scarring diffuse alopecia, with characteristic clinical, dermoscopic, and histological patterns. Vitamin D receptor (VDR) is expressed in follicular keratinocytes and dermal papilla cells and is shown to have important role in hair growth and regulation of hair cycle. VDR polymorphism was not extensively investigated in hair disorders including FPHL.

Aim

To investigate the association between VDR gene polymorphism (Cdx-1 and Taq-1) and FPHL to explore if these polymorphisms affect the disease occurrence or influence its clinical presentation.

Methods

A case-control study was conducted on 30 female patients with FPHL and 30 age-matched female healthy subjects, as a control group. Degree of hair loss was assessed by Ludwig grading. VDR gene polymorphisms, Taq-1 and Cdx-1 were investigated by real time polymerase chain reaction.

Results

CC genotype, TC genotype, and T allele of Taq-1 were more prevalent in FPHL patients than in control group. They increased disease risk by 12.6, 2.1, and 2.9 folds, respectively. AA genotype, GA genotype, and G allele of Cdx-1 were significantly more prevalent among FPHL patients than in control group. They increased disease risk by 7.5, 5.2, and 5.5 folds, respectively.

Conclusion

Taq-1 and Cdx-1 can be considered as risk factors for FPHL. They may play role in disease persistence rather than disease initiation. This association may be explained by failure of new anagen growth and decreased proliferation of hair follicle stem cells. Further studies are recommended to confirm current findings.

Vitamin D Receptor Gene Polymorphism In Chronic Telogen Effluvium; A Case-Control Study

Background

Telogen effluvium (TE) is a form of alopecia characterized by diffuse hair shedding. Vitamin D receptor (VDR) plays a role in hair cycle regulation as it is expressed in follicular keratinocytes and dermal papilla cells.

Purpose

To investigate the association between Cdx1 and Taq1 VDR gene polymorphisms and chronic TE.

Methods

Thirty female patients with chronic TE were selected and 30 healthy, age- and sex-matched volunteers were included as a control group. Detection of VDR gene polymorphisms Taq1 and Cdx1 was done by real-time polymerase chain reaction.

Results

Regarding Taq 1, CC genotype was present in 30% of cases versus 3.3% of controls. TC genotype was present in 33.3% of cases and 36.7% of controls. CC genotype was significantly associated with cases (P=0.01). It increases the risk of chronic TE by 14.7 folds. C allele was significantly associated with patient group (P=0.004). It increases the risk of disease occurrence by 3.1 folds. Regarding Cdx1, AA genotype was present in 6.7% of cases versus 3.3% of controls. GA genotype was present in approximately 30% of cases and 6.7% of controls. GA genotype was significantly associated with cases (P=0.03). It increases the risk of chronic TE by 6.3 folds. A allele was significantly associated with patient group (P=0.007). It increases the risk of disease occurrence by 3.8 folds.

Limitations

The main limitation is the small number of cases due to the time and financial constraints. Only chronic TE was analyzed, therefore, other types should be investigated in the following studies.

Conclusion

After exposure to primary physical or mental stressor, hair follicles are stimulated to enter prematurely into telogen and shed out. In individuals with Taq1 and Cdx1 polymorphisms, the disease persists as a result of prevention of new anagen growth and inhibition of hair follicle stem cell proliferation.

Alopecia areata: a review of disease pathogenesis

BACKGROUND

Alopecia areata is a disorder that results in nonscarring hair loss. The psychological impact can be significant, leading to feelings of depression and social isolation. Objectives In this article, we seek to review the pathophysiological mechanisms proposed in recent years in a narrative fashion.

METHODS

We searched MEDLINE and Scopus for articles related to alopecia areata, with a particular emphasis on its pathogenesis.

RESULTS

The main theory of alopecia areata pathogenesis is that it is an autoimmune phenomenon resulting from a disruption in hair follicle immune privilege. What causes this breakdown is an issue of debate. Some believe that a stressed hair follicle environment triggers antigen presentation, while others blame a dysregulation in the central immune system entangling the follicles. Evidence for the latter theory is provided by animal studies, as well investigations around the AIRE gene. Different immune-cell lines including plasmacytoid dendritic cells, natural killer cells and T cells, along with key molecules such as interferon-γ, interleukin-15, MICA and NKG2D, have been identified as contributing to the autoimmune process.

CONCLUSIONS

Alopecia areata remains incurable, although it has been studied for years. Available treatment options at best are beneficial for milder cases, and the rate of relapse is high. Understanding the exact mechanisms of hair loss in alopecia areata is therefore of utmost importance to help identify potential therapeutic targets.

The Role of Micronutrients in Alopecia Areata: A Review

Alopecia areata (AA) is a common, non-scarring form of hair loss caused by immune-mediated attack of the hair follicle. As with other immune-mediated diseases, a complex interplay between environment and genetics is thought to lead to the development of AA. Deficiency of micronutrients such as vitamins and minerals may represent a modifiable risk factor associated with development of AA. Given the role of these micronutrients in normal hair follicle development and in immune cell function, a growing number of investigations have sought to determine whether serum levels of these nutrients might differ in AA patients, and whether supplementation of these nutrients might represent a therapeutic option for AA. While current treatment often relies on invasive steroid injections or immunomodulating agents with potentially harmful side effects, therapy by micronutrient supplementation, whether as a primary modality or as adjunctive treatment, could offer a promising low-risk alternative. However, our review highlights a need for further research in this area, given that the current body of literature largely consists of small case-control studies and case reports, which preclude any definite conclusions for a role of micronutrients in AA. In this comprehensive review of the current literature, we found that serum vitamin D, zinc, and folate levels tend to be lower in patients with AA as compared to controls. Evidence is conflicting or insufficient to suggest differences in levels of iron, vitamin B12, copper, magnesium, or selenium. A small number of studies suggest that vitamin A levels may modify the disease. Though understanding of the role for micronutrients in AA is growing, definitive clinical recommendations such as routine serum level testing or therapeutic supplementation call for additional studies in larger populations and with a prospective design.

Estimated serum vitamin D status, vitamin D intake, and risk of incident alopecia areata among US women

Studies have identified increased prevalence of vitamin D deficiency in patients with alopecia areata (AA), an autoimmune disease characterized by hair loss, but none have prospectively examined vitamin D status and incident AA. In 55,929 women in the Nurses' Health Study (NHS), we prospectively evaluated the association between estimated vitamin D status, derived from a prediction model incorporating lifestyle determinants of serum vitamin D, and self-reported incident AA. We evaluated dietary, supplemental, and total vitamin D intake as additional exposures. Using Cox proportional hazards models, we calculated age-adjusted and multivariate hazard ratios (HR) to evaluate risk of AA. We identified 133 cases of AA over a follow-up of 12 years. The age-adjusted HR between top vs. bottom quartiles for serum vitamin D score was 0.94 (95 % CI 0.60-1.48) and the corresponding multivariate HR was 1.08 (95 % CI 0.68-1.73). There was no significant association between dietary, supplemental, or total vitamin D intake and incident AA. This study does not support a preventive role for vitamin D in the risk of developing AA.

Vitamin D in systemic and organ-specific autoimmune diseases

Lately, vitamin D has been linked with metabolic and immunological processes, which established its role as an essential component of human health preservation. Vitamin D has been defined as natural immune modulators, and upon activation of its receptors (VDRs), it regulates calcium metabolism, cellular growth, proliferation and apoptosis, and other immunological functions. Epidemiological data underline a strong correlation between poor vitamin D status and higher risk for chronic inflammatory illnesses of various etiologies, including autoimmune diseases. Epidemiological, genetic, and basic studies indicated a potential role of vitamin D in the pathogenesis of certain systemic and organ-specific autoimmune diseases. These studies demonstrate correlation between low vitamin D and prevalence of diseases. In addition, VDRs' polymorphisms observed in some of these autoimmune diseases may further support a plausible pathogenic link. Notably, for some autoimmune disease, no correlation with vitamin D levels could be confirmed. Thus, in the current review we present the body of evidence regarding the plausible roles of vitamin D and VDR's polymorphism in the pathogenesis of autoimmunity. We summarize the data regarding systemic (i.e., systemic lupus erythematosus, rheumatoid arthritis, etc.) and organ-specific (i.e., multiple sclerosis, diabetes mellitus, primary biliary cirrhosis, etc.) autoimmune diseases, in which low level of vitamin D was found comparing to healthy subjects. In addition, we discuss the correlations between vitamin D levels and clinical manifestations and/or activity of diseases. In this context, we address the rational for vitamin D supplementation in patients suffering from autoimmune diseases. Further studies addressing the mechanisms by which vitamin D affects autoimmunity and the proper supplementation required are needed.

Functional polymorphisms in cell death pathway genes FAS and FAS ligand and risk of alopecia areata

FAS and FAS ligand (FASLG) are important proapoptotic proteins that have a significant function in regulating cell growth and apoptosis and play essential roles in many human autoimmune diseases. Alopecia areata (AA) is hypothesized to be an organ-specific autoimmune disease mediated by T cells to the hair follicles. The concept of an autoimmune mechanism as the basis for AA led us to investigate a possible association between the FAS and FASLG polymorphism with AA susceptibility and disease progression on AA patients in Turkish population. The study group consisted of 118 unrelated patients with AA and 118 unrelated healthy controls. We genotyped FAS-670 A/G and FASLG-124 A/G polymorphisms and assessed their association with AA risk. A statistically significant difference was observed between patients and controls according to genotype frequencies of FAS gene (p = 0.0002). GG genotype of 670 A/G polymorphism was found to be protective against AA (p = 0.000, OR 0.07, 95 % CI 0.00-0.41). It can be concluded there is a reduced risk of AA risk appeared to be associated with FAS-670 A/G. No association was observed between AA patients and controls according to genotype and allele distribution of FASLG gene 124 A/G polymorphism (p = 0.1297, p = 453, respectively). In conclusion, we provide evidence that FAS/FASLG polymorphisms may have an effect on the risk of AA in the Turkish population. These findings provide an additional support to a genetic basis for AA development.

Nutrition and hair: deficiencies and supplements

Hair follicle cells have a high turnover. A caloric deprivation or deficiency of several components, such as proteins, minerals, essential fatty acids, and vitamins, caused by inborn errors or reduced uptake, can lead to structural abnormalities, pigmentation changes, or hair loss, although exact data are often lacking. The diagnosis is established through a careful history, clinical examination of hair loss activity, and hair quality and confirmed through targeted laboratory tests. Examples of genetic hair disorders caused by reduced nutritional components are zinc deficiency in acrodermatitis enteropathica and copper deficiency in Menkes kinky hair syndrome.