RESUMO
Albinism is a genetic condition expressed as a lack of integumentary and retinal melanin. Although documented across many vertebrate species, albinism and other skin disorders are rarely observed in elasmobranchs (sharks and rays). The present study describes the first confirmed case of albinism in American cownose ray (Rhinoptera bonasus), and three other juveniles of the species with undetermined skin disorders observed in São Paulo, southeastern Brazil. Pigmentation disorders have already been observed in American cownose rays from the North Atlantic, including two cases of leucism and a possible albinism. Based on the results, it was discussed the possible consequences of albinism for the ray survival as well as the possible causes for the undetermined skin disorders.
Assuntos
Albinismo , Tubarões , Rajidae , Animais , Brasil , Pele , Albinismo/genéticaRESUMO
Albinism is a genetic disorder that results in a deficiency in melanin production. This type of chromatic alteration may affect several vertebrate species, but is rarely observed in nature. In Brazil, for the bat group, only 15 albino individuals have been registered. Here we present a new case for Artibeus planirostris. A pregnant female of this species with alopecia was captured in the Caatinga biome. A compilation of the distribution of albino bats in Brazil is presented.
Assuntos
Albinismo , Quirópteros , Albinismo/genética , Albinismo/veterinária , Animais , Brasil , Ecossistema , FemininoRESUMO
Albinism is the most common color variation described in fish and is characterized by a white or yellow phenotype according to the species. In rainbow trout Oncorhynchus mykiss, aside from yellow-albino phenotypes, cobalt blue variants with autosomal, recessive inheritance have also been reported. In this study, we investigated the inheritance pattern and chromatophores distribution/abundance of cobalt blue trouts obtained from a local fish farm. Based on crosses with wild-type and dominant yellow-albino lines, we could infer that cobalt blue are dominant over wild-type and co-dominant in relation to yellow-albino phenotype, resulting in a fourth phenotype: the white-albino. Analysis of chromatophores revealed that cobalt blue trouts present melanophores, as the wild-type, and a reduced number of xanthophores. As regards to the white-albino phenotype, they were not only devoid of melanophores but also presented a reduced number of xanthophores. Cobalt blue and white-albino trouts also presented reduced body weight and a smaller pituitary gland compared to wild-type and yellow-albino phenotypes. The transcription levels of tshb and trh were up regulated in cobalt blue compared to wild type, suggesting the involvement of thyroid hormone in the expression of blue color. These phenotypes represent useful models for research on body pigmentation in salmonids and on the mechanisms behind endocrine control of color patterning.
Assuntos
Albinismo/genética , Padrões de Herança/genética , Oncorhynchus mykiss/genética , Pigmentação/genética , Animais , Cromatóforos/metabolismo , Cor , Melanóforos/metabolismo , Oncorhynchus mykiss/crescimento & desenvolvimento , FenótipoRESUMO
Oculocutaneous albinism is an autosomal recessive disease caused by the complete absence or decrease of melanin biosynthesis in melanocytes. Due to the reduction or absence of melanin, albinos are highly susceptible to the harmful effects of ultraviolet radiation and are at increased risk of actinic damage and skin cancer. In Brazil, as in other parts of the world, albinism remains a little known disorder, both in relation to epidemiological data and to phenotypic and genotypic variation. In several regions of the country, individuals with albinism have no access to resources or specialized medical care, and are often neglected and deprived of social inclusion. Brazil is a tropical country, with a high incidence of solar radiation during the year nationwide. Consequently, actinic damage and skin cancer occur early and have a high incidence in this population, often leading to premature death. Skin monitoring of these patients and immediate therapeutic interventions have a positive impact in reducing the morbidity and mortality associated with this condition. Health education is important to inform albinos and their families, the general population, educators, medical professionals, and public agencies about the particularities of this genetic condition. The aim of this article is to present a review of the epidemiological, clinical, genetic, and psychosocial characteristics of albinism, with a focus in skin changes caused by this rare pigmentation disorder.
Assuntos
Albinismo/genética , Albinismo/patologia , Albinismo/complicações , Albinismo/epidemiologia , Brasil/epidemiologia , Carcinoma Basocelular/etiologia , Carcinoma Basocelular/patologia , Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Ceratose Actínica/etiologia , Ceratose Actínica/patologia , Masculino , Melaninas/deficiência , Prevalência , Fatores de Risco , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/fisiopatologia , Raios Ultravioleta/efeitos adversosRESUMO
Abstract Oculocutaneous albinism is an autosomal recessive disease caused by the complete absence or decrease of melanin biosynthesis in melanocytes. Due to the reduction or absence of melanin, albinos are highly susceptible to the harmful effects of ultraviolet radiation and are at increased risk of actinic damage and skin cancer. In Brazil, as in other parts of the world, albinism remains a little known disorder, both in relation to epidemiological data and to phenotypic and genotypic variation. In several regions of the country, individuals with albinism have no access to resources or specialized medical care, and are often neglected and deprived of social inclusion. Brazil is a tropical country, with a high incidence of solar radiation during the year nationwide. Consequently, actinic damage and skin cancer occur early and have a high incidence in this population, often leading to premature death. Skin monitoring of these patients and immediate therapeutic interventions have a positive impact in reducing the morbidity and mortality associated with this condition. Health education is important to inform albinos and their families, the general population, educators, medical professionals, and public agencies about the particularities of this genetic condition. The aim of this article is to present a review of the epidemiological, clinical, genetic, and psychosocial characteristics of albinism, with a focus in skin changes caused by this rare pigmentation disorder.
Assuntos
Humanos , Masculino , Feminino , Albinismo/genética , Albinismo/patologia , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/fisiopatologia , Raios Ultravioleta/efeitos adversos , Brasil/epidemiologia , Carcinoma Basocelular/etiologia , Carcinoma Basocelular/patologia , Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/patologia , Albinismo/complicações , Albinismo/epidemiologia , Prevalência , Fatores de Risco , Ceratose Actínica/etiologia , Ceratose Actínica/patologia , Melaninas/deficiênciaRESUMO
Understanding the genetic basis of trait evolution is critical to identifying the mechanisms that generated the immense amount of diversity observable in the living world. However, genetically manipulating organisms from natural populations with evolutionary adaptations remains a significant challenge. Astyanax mexicanus exists in two interfertile forms, a surface-dwelling form and multiple independently evolved cave-dwelling forms. Cavefish have evolved a number of morphological and behavioral traits and multiple quantitative trait loci (QTL) analyses have been performed to identify loci underlying these traits. These studies provide a unique opportunity to identify and test candidate genes for these cave-specific traits. We have leveraged the CRISPR/Cas9 genome editing techniques to characterize the effects of mutations in oculocutaneous albinism II (oca2), a candidate gene hypothesized to be responsible for the evolution of albinism in A. mexicanus cave populations. We generated oca2 mutant surface A. mexicanus. Surface fish with oca2 mutations are albino due to a disruption in the first step of the melanin synthesis pathway, the same step that is disrupted in albino cavefish. Hybrid offspring from crosses between oca2 mutant surface and cavefish are albino, definitively demonstrating the role of this gene in the evolution of albinism in this species. This research elucidates the role oca2 plays in pigmentation in fish, and establishes that this gene is solely responsible for the evolution of albinism in multiple cavefish populations. Finally, it demonstrates the utility of using genome editing to investigate the genetic basis of trait evolution.
Assuntos
Sistemas CRISPR-Cas , Caraciformes/genética , Proteínas de Peixes/genética , Edição de Genes , Melatonina/genética , Proteínas de Membrana Transportadoras/genética , Pigmentação/genética , Albinismo/genética , Albinismo/metabolismo , Animais , Caraciformes/metabolismo , Proteínas de Peixes/metabolismo , Melatonina/biossíntese , Proteínas de Membrana Transportadoras/metabolismoRESUMO
Albinism is a diverse group of hypopigmentary disorders caused by multiple-genetic defects. The genetic diagnosis of patients affected with albinism by Sanger sequencing is often complex, expensive, and time-consuming. In this study, we performed targeted next-generation sequencing to screen for 16 genes in a patient with albinism, and identified 21 genetic variants, including 19 known single nucleotide polymorphisms, one novel missense mutation (c.1456 G>A), and one disease-causing mutation (c.478 G>C). The novel mutation was not observed in 100 controls, and was predicted to be a damaging mutation by SIFT and Polyphen. Thus, we identified a novel mutation in SLC45A2 in a Chinese family, expanding the mutational spectrum of albinism. Our results also demonstrate that targeted next-generation sequencing is an effective genetic test for albinism.
Assuntos
Albinismo/genética , Antígenos de Neoplasias/genética , Proteínas de Membrana Transportadoras/genética , Antígenos de Neoplasias/metabolismo , China , Análise Mutacional de DNA/métodos , Feminino , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Lactente , Proteínas de Membrana Transportadoras/metabolismo , Mutação , Linhagem , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Reports about albinism in rodents are common. In the family Echimyidae, however, albinism is very rare. This is the second case of coat color variation reported within Echimyidae and the first for the genus Thrichomys. The pelages of Thrichomys pachyurus individuals with normal and variant coat color were observed under a fluorescent artificial light and were examined with a stereoscopic microscope. The descriptions of pelage color were based on the book Color Standards and Color Nomenclature. The predominantly white pattern of coat color in individuals of T. pachyurus suggests a partial albinism caused by delay in migration time of melanoblasts from neural crest to epidermis. The habitat of T. pachyurus has a heavy vegetative cover, which offers natural protection against predators and high-quality nutrition.(AU)
Assuntos
Animais , Albinismo/genética , Crista Neural/anatomia & histologia , Roedores/classificaçãoRESUMO
Herein we document the first case of albinism in Black Mastiff bat Molossus rufus É. Geoffroy St.-Hilaire, 1805. The specimen was collected in Iquitos City (Northwestern Peru); it was an adult male with ventral and dorsal white pelage, red eyes, and depigmented wing membranes, nose leafs and ears.(AU)
Assuntos
Animais , Quirópteros , Albinismo/genética , Anormalidades da Pele/genética , Melaninas/deficiência , Melaninas/genéticaRESUMO
Albinism is a phenomenon present in many vertebrate species, and can be defined as the absence of normal pigmentation of an organism. In bats, complete albinism is considered a rare phenomenon, and its occurrence was recorded for less than 4% of all existing bat species. On 6 September 2012, an individual of Carollia perspicillata (Linnaeus, 1758) was captured in Igaporã, Bahia, and it had all characteristics of complete albinism, lacking normal pigmentation over the entire body surface, including the iris. The purpose of this paper is to report the first record of complete albinism in Carollia perspicillata and thereby increase the number of species recorded with such anomalies; in addition to contributing to the understanding of this pigmentation disorder.(AU)