What’s new in hair — January 2016 | Dr. Yuval Ramot

Disease causing homozygous variants in the human hairless gene

Int J Dermatol. 2015 Dec 18. doi: 10.1111/ijd.13109. [Epub ahead of print]

Atrichia with papular lesions (APL) is a genetic hair disease, caused by mutations in the HR gene, which encodes a nuclear receptor co-repressor. APL is characterized by complete loss of scalp hair, and shedding of hair from other places in the body. In this study, Mehmood et al. describe five consanguineous Pakistani families, with features of APL. They tested all five families for linkage using microsatellite markers flanking the HR gene and its regulatory region (U2HR), and found linkage to the HR gene in all the families tested. Sequencing of the gene in all five families revealed a novel homozygous nonsense variant in one family, and two additional pathogenic variants in the other four families. These variants have been published previously. It should be noted that all patients with APL are affected to the same degree of clinical severity, regardless of the nature of the mutation. In one of the families, the affected members displayed thick, loose, and folded skin, presumably due to dilation of the hair follicle. This phenotype is unique in APL, and is reminiscent of the clinical phenotype observed in the HR mouse. This study expands the spectrum of mutations in the HR gene resulting in APL, and suggests that APL is not as rare as previously suspected.

 

Structural and functional analysis of intact hair follicles and pilosebaceous units by volumetric multispectral optoacoustic tomography

J Invest Dermatol. 2015 Dec 29. pii: S0022-202X(15)00240-7. doi: 10.1016/j.jid.2015.09.001. [Epub ahead of print]

The diagnosis of hair disorders in humans and research of hair morphology and function rely mostly on skin biopsies, which are invasive and harbour several technical difficulties. Therefore, non-invasive imaging approaches show promise as a method to visualize the hair follicle. However, current imaging methods, such as reflectance confocal imaging or OCT, are limited by the spatial resolution and the optical diffusion limit. Ford et al. developed a high-resolution volumetric multispectral optoacoustic tomography, and in this study, they present its visualization advantages. This novel imaging method provides high resolution, label-free 3D visualization of the structures of the hair follicle at imaging depths beyond several millimetres. They show that this method can also provide a sensitive spatial assessment of melanin in the hair shaft, thereby allowing characterization of hairs of different colors. This tool can also help assess hemoglobin in blood vessels and dermal papilla, and lipids in the sebaceous glands and hypodermal fat. Such as tool can be harnessed to study the phase characteristics of the hair follicle, and possibly provide means to assess potential treatments for hair disorders.

 

Efficacy and safety of methotrexate combined with low- to moderate-dose corticosteroids for severe alopecia areata

Dermatology. 2016 Jan 7. [Epub ahead of print]

Although a large number of treatment modalities are being used for alopecia areata (AA), randomized controlled trials evaluating their efficacy are sparse, and currently there is no FDA approved treatment for AA. One possible treatment is methotrexate, either alone or in combination with corticosteroids. Anuset et al. performed a retrospective monocentric study to assess the efficacy and safety of this treatment for severe AA patients. A total of 26 patients were included in this study. The authors report on high response rates in the treated patients. However, many patients experienced side effects, and furthermore, many patients had relapse of disease either while on treatment or after stopping the treatment. These results are similar to previous reports on the use of methotrexate for AA. Based on this and previous studies, this combination should be considered with great caution for AA patients, taking into consideration the high relapse rate and the potential side effects.

 

An observational retrospective evaluation of 79 young men with long-term adverse effects after use of finasteride against androgenetic alopecia.

Andrology. 2016 Jan 13. doi: 10.1111/andr.12147. [Epub ahead of print]

Finasteride is a very popular drug to treat androgenetic alopecia (AGA), which has been approved by the FDA for almost 20 years for this indication. However, recently, there is increasing concern regarding potential adverse effects of this drug, which can even persist for several years after stopping treatment. In this study, Chiriaco et al. describe the clinical symptoms in 79 men who were treated with finasteride for AGA, and who had sexual or non-sexual adverse effects for over 6 months after stopping finasteride treatment. Common side effects that were reported include difficulty in getting and keeping erection, difficulty in reaching orgasm, loss of penis sensitivity, decreased ejaculatory force and low penile temperature. Non-sexual side effects include reduced feeling of life pleasure or emotions (anhedonia), lack of mental concentration, and loss of muscle tone/mass. This study can help dermatologists to better diagnose side effects that are related to finasteride treatment.

 

Functional interpretation of genome-wide association study evidence in alopecia areata.

J Invest Dermatol. 2016 Jan;136(1):314-7. doi: 10.1038/JID.2015.402.

Recently, Betz et al. published the first meta-analysis GWAS in alopecia areata (AA), and identified a total of 14 associated genomic regions, which encompass both protein-coding genes and regulatory features that can affect the expression of genes in neighbouring regions. However, it is still unclear which gene or set of genes at or near an associated linkage disequilibrium block play a role in AA pathogenesis. In order to address this question, Petukhova and Christiano performed pathway and network analyses to characterize functional patterns in genes across the GWAS loci. They identified 225 protein-coding genes, and using three different analytic techniques to distinguish etiological processes encoded by GWAS statistical evidence, 159 of the 225 genes were implicated. These genes converge on several immunological pathways and processes, and emphasize the importance of the JAK-STAT signalling pathway in AA. This study can help to develop a biomarker panel for AA, and could also be used for interpretation of additional next-generation sequencing studies.

 

Factors affecting the severity of central centrifugal cicatricial alopecia

Int J Dermatol. 2016 Jan 15. doi: 10.1111/ijd.13061. [Epub ahead of print]

Central centrifugal cicatricial alopecia (CCCA) is a scarring hair disorder, which is prevalent mostly among African-American women. It is assumed to be associated with different hair care practices, although its exact risk factors and pathogenesis are still unclear. Suchonwanit et al. performed a cross-sectional survey study, involving 38 women with biopsy-confirmed CCCA. They found that the duration of hair loss is positively associated with the severity of disease. Furthermore, they show that androgen-related conditions are prevalent in those affected with CCCA. They conclude that much is still obscure about CCCA pathogenesis, and therefore treatment options for this condition are still very limited.

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