Complex segregation analysis of facial melasma in Brazil: evidence for a genetic susceptibility with a dominant pattern of segregation

Holmo, Nicole França; Ramos, Geovana Brotto; Salomão, Heloisa; Werneck, Renata Iani; Mira, Marcelo Távora; Miot, Luciane Donida Bartoli; Miot, Hélio Amante

doi:10.1007/s00403-018-1861-5

Cited by 20 publications

(22 citation statements)

References 19 publications

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“…The locations of melasma in visible areas, the young age of patients and the frequent relapse (even during treatment) result in a considerable impact on the quality of life 1 . Facial melasma is independently associated with miscegenation and the high occurrence within familiars (40%~60%) suggests a genetic predisposition, which is best explicated by a dominant pattern of segregation 2,3 .…”

Section: Introductionmentioning

confidence: 99%

Exploratory Study of Epidermis, Basement Membrane Zone, Upper Dermis Alterations and Wnt Pathway Activation in Melasma Compared to Adjacent and Retroauricular Skin

et al. 2020

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Background: Melasma is a chronic acquired focal hypermelanosis which pathogenesis has not been fully elucidated. Classical pathophysiologic studies have analysed the affected and perilesional areas, but little is known about the status of sun-protected skin, which is subjected to the same endogenous and genetic factors. Objective: To assess the histological characteristics of melasma compared to adjacent and retroauricular skin. Methods: Skin samples were collected from 10 female from: melasma, perilesional area and retroauricular. The samples were stained (haematoxylin-eosin, periodic acid-Schiff, Fontana-Masson, picrosirius red, toluidine blue and Verhoeff), immunolabelled for CD34 and Wnt1. The data from the skin sites were analysed simultaneously by a multivariate model. Results: Melasma skin exhibited noteworthy stratum corneum compaction, greater collagen heterogeneity, solar elastosis, higher number of mast cells, basement membrane zone (BMZ) damage, Wnt1 expression, pendulum melanocytes, higher cellularity and vascular proliferation at the superficial dermis. Stratum cor-neum compaction, collagen heterogeneity and BMZ abnormalities were variables associated to melasma that not follow a continuum through retroauricular to adjacent skin. Mast cell count was the variable that disclosed correlation with the most other abnormalities as well as had the greater contribution in the multivariate model. Conclusion: In addition to melanocyte hyperactivity, melasma skin exhibits alterations in the epidermal barrier, upper dermis and BMZ, which differ from the adjacent sun-exposed skin and retroauricular skin, indicating a distinct phenotype, rather than a mere extension of photoageing or intrinsic ageing. Mast cells appear to play a central role in the physiopathology of melasma.

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Section: Introductionmentioning

confidence: 99%

Exploratory Study of Epidermis, Basement Membrane Zone, Upper Dermis Alterations and Wnt Pathway Activation in Melasma Compared to Adjacent and Retroauricular Skin

et al. 2020

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“… 3 Its pathophysiology is still not completely understood, but there is an interaction between genetics (autosomal dominant inheritance), hormonal factors, and exposure to solar radiation, leading to greater focal melanogenesis. 3 , 4 , 5 , 6 , 7 …”

Section: Introductionmentioning

confidence: 99%

Evaluation of ex vivo melanogenic response to UVB, UVA, and visible light in facial melasma and unaffected adjacent skin

Alcântara

Espósito

Olivatti

et al. 2020

Anais Brasileiros de Dermatologia

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Background The independent role of solar radiation in the differential melanogenesis between melasma and adjacent skin is unknown. Objectives To assess the melanogenic responses of skin with facial melasma and of the adjacent skin to UVB, UVA, and visible light, in an ex vivo model. Methods This was a quasi-experimental study involving 22 patients with melasma. Facial melasma and adjacent skin samples were collected and stored in DMEM medium, at room temperature. One fragment was placed under the protection from light, while another was exposed to UVB, UVA, and visible light (blue-violet component): 166 mJ/cm 2 , 1.524 J/cm 2 , and 40 J/cm 2 , respectively. Subsequently, all samples were kept for 72 hours in a dark environment and stained by Fontana-Masson to assess basal layer pigmentation, dendrites, and melanin granulation. Results Effective melanogenesis was observed in the basal layer in melasma and in the normal adjacent skin after all irradiations ( p < 0.01), with the following median increment: UVB (4.7% vs . 8.5%), UVA (9.5% vs . 9.9%), and visible light (6.8% vs . 11.7%), with no significant difference between anatomical sites. An increase in melanin granulation (coarser melanosomes) was observed only after irradiation with UVA and only in the skin with melasma ( p = 0.05). An increase in the melanocyte dendrite count induced by UVB radiation was observed in both anatomical sites ( p ≤ 0.05). Study limitations Use of an ex vivo model, with independent irradiation regimes for UVB, UVA, and visible light. Conclusions Melanogenesis induced by UVB, UVA, and visible light was observed both in melasma and in the adjacent skin. The morphological patterns suggest that different irradiations promote individualized responses on the skin with melasma.

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“…Notwithstanding the study of patterns of segregation in multifactorial diseases requires several families and broad epidemiological data, the suggested pattern of segregation throughout this family is autosomal dominant as hypothesized previously by Tziotzios et al 5,20 . The genetic study of other numerous Brazilian families with FFA in order to explore the segregation pattern validate these haplotypes and understand the role of environmental exposure is warranted.…”

Section: Resultsmentioning

confidence: 66%

A large familial cluster and sporadic cases of frontal fibrosing alopecia in Brazil reinforce known human leucocyte antigen (HLA) associations and indicate new HLA susceptibility haplotypes

Ramos

Garbers

Silva

et al. 2020

Acad Dermatol Venereol

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Background Frontal fibrosing alopecia (FFA) is a lymphocytic scarring alopecia whose worldwide incidence is rising. Environmental triggers combined with genetic predisposition represent one of the current hypotheses in FFA aetiology. Familial clusters are opportunities to investigate the genetic basis of diseases. Objectives Assess human leucocyte antigen (HLA) genetic variability in a Brazilian sample of a large familial cluster (six sisters and one daughter) with FFA, unnafected familiar members and sporadic cases of FFA. Methods We addressed the HLA-A, HLA-B, HLA-C, HLA-G and HLA-E genetic variability in this family and in seven sporadic FFA cases, comparing allele frequencies with those reported for the São Paulo State from Brazil. Results Two susceptibility haplotypes, C

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Complex segregation analysis of facial melasma in Brazil: evidence for a genetic susceptibility with a dominant pattern of segregation

Cited by 20 publications

References 19 publications

Exploratory Study of Epidermis, Basement Membrane Zone, Upper Dermis Alterations and Wnt Pathway Activation in Melasma Compared to Adjacent and Retroauricular Skin

Exploratory Study of Epidermis, Basement Membrane Zone, Upper Dermis Alterations and Wnt Pathway Activation in Melasma Compared to Adjacent and Retroauricular Skin

Evaluation of ex vivo melanogenic response to UVB, UVA, and visible light in facial melasma and unaffected adjacent skin

A large familial cluster and sporadic cases of frontal fibrosing alopecia in Brazil reinforce known human leucocyte antigen (HLA) associations and indicate new HLA susceptibility haplotypes

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