RESUMO
BACKGROUND: Pigmented and albino rabbits are commonly used in visual research; however, the lack of pigment in the eyes may affect retinal responses. Here, we compare and describe the differences of retinal function between pigmented (English Butterfly) and albino (New Zealand) rabbits. METHODS: Electroretinograms were recorded in pigmented and albino rabbits in the dark-adapted eye, in the light-adapted eye and for four temporal frequencies in the light-adapted eye. The implicit time and amplitude of the a- and b-waves were analyzed, as well as the amplitude and phase of the first harmonic component of the photopic flicker response. RESULTS: Albino rabbits presented significantly larger amplitudes for both a- and b-waves at all intensities and frequencies. The intensity-response function of the scotopic b-wave also showed that the albino retina is more sensitive than the pigmented retina and the larger flicker amplitudes found in the albino group also revealed post-receptoral changes specifically related to cone pathways. CONCLUSIONS: The larger amplitude of albino receptoral and post-receptoral activities might be attributed to greater availability of light due to scatter and reflection at the retinal layer, and as the differences in response amplitudes between the groups increase with flicker frequency, we suggest that ON bipolar cells recover faster in the albino group, suggesting that this might be a mechanism to explain the higher temporal resolution for albinos compared to the pigmented group.
Assuntos
Albinismo Oculocutâneo/fisiopatologia , Eletrorretinografia , Coelhos/fisiologia , Retina/fisiologia , Animais , Visão de Cores/fisiologia , Adaptação à Escuridão , Visão Noturna/fisiologia , Estimulação Luminosa , Células Fotorreceptoras Retinianas Cones/fisiologia , Pigmentação da PeleRESUMO
PURPOSE: To evaluate the benefits of phacoemulsification and intraocular lens implantation in patients with oculocutaneous albinism (OCA). METHOD: The charts of 195 patients with OCA who visited a local eye clinic were reviewed. All of these patients had genetic linkage analysis to establish OCA type. Frequencies and Paired t-test analysis were determined. RESULTS: Of the 195 patients, nine (4.6%) underwent clear cornea phacoemulsification with intraocular lens implantation. Seven of the nine patients with OCA had the Hermansky-Pudlak (HPS) type 1; two had OCA type 1. Pre-operative BCVA of all eyes ranged from 1.0 to 2.3 logMAR with a mean of 1.42 logMAR and a standard deviation of 0.41 logMAR. Post-operative BCVA of all eyes ranged from 1.0 to 1.30 logMAR with a mean of 1.04 logMAR and a standard deviation of 0.10 logMAR. BCVA improved after phacoemulsification surgery and intraocular lens implantation (p = 0.002). Pre-operative astigmatism of all eyes ranged from +0.50 to +5.75 with a mean of +2.25 and a standard deviation of +2.40. Post-operative astigmatism of all eyes ranged from +0.50 to +2.00 with a mean of +1.23 and a standard deviation of +0.42. Astigmatism improved after phacoemulsification surgery and intraocular lens implantation (p = 0.05). CONCLUSION: Nine patients with OCA who underwent phacoemulsification and intraocular lens implant experienced improved visual acuity and reduced astigmatism post-operatively. These results suggest cataract surgery may improve vision and refractive errors, and thus quality of life, in patients with albinism.
Assuntos
Albinismo Oculocutâneo/complicações , Catarata/complicações , Implante de Lente Intraocular , Facoemulsificação , Adulto , Albinismo Oculocutâneo/fisiopatologia , Albinismo Oculocutâneo/psicologia , Astigmatismo/fisiopatologia , Catarata/fisiopatologia , Catarata/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pseudofacia/fisiopatologia , Qualidade de Vida/psicologia , Refração Ocular/fisiologia , Estudos Retrospectivos , Acuidade Visual/fisiologiaRESUMO
BACKGROUND: The social reality of the albino needs to be more studied in Brazil, as myths and social segregation regarding this illness are likely to be found in the country, with psychosocial and medical implications. OBJECTIVE: As this subject has not been referenced in previous scientific articles in Brazil, this research intends to evaluate the quality of life of the albinos that treated at our medical institution. METHODS: The quality of life was evaluated through the WHOQOL-BREF. Furthermore, two aspects of main relevance in the lives of the albinos were also objects of research, low vision and skin cancer. The sample consisted of forty oculocutaneous albinos and a control group of forty healthy individuals, matched by sex and age. RESULTS: Among the participants, 57.7% were between 18 and 40 years old, 28.2% were between 41 and 60, and 14.1% were over 60. 42.1% had skin cancer before the study, 18.4% had skin cancer during the study and 89.5% stated visual deficit. The results obtained in the questionnaires showed a statistically significant difference in the physical domain, with P < 0.001. CONCLUSION: Low vision combined with skin lesions and social stigma may contribute to disturbances in the quality of life of oculocutaneous albinos. The results presented in this study demonstrated the vulnerability of the affected individuals and the special care required by those patients, at the same time that the need for further research is highlighted in order to better elucidate the aspects related to albinism.
Assuntos
Albinismo Oculocutâneo/psicologia , Qualidade de Vida/psicologia , Adolescente , Adulto , Distribuição por Idade , Albinismo Oculocutâneo/fisiopatologia , Brasil , Métodos Epidemiológicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria/métodos , Estigma Social , Fatores Sociológicos , Adulto JovemRESUMO
AbstractBACKGROUND:The social reality of the albino needs to be more studied in Brazil, as myths and social segregation regarding this illness are likely to be found in the country, with psychosocial and medical implications.OBJECTIVE:As this subject has not been referenced in previous scientific articles in Brazil, this research intends to evaluate the quality of life of the albinos that treated at our medical institution.METHODS:The quality of life was evaluated through the WHOQOL-BREF. Furthermore, two aspects of main relevance in the lives of the albinos were also objects of research, low vision and skin cancer. The sample consisted of forty oculocutaneous albinos and a control group of forty healthy individuals, matched by sex and age.RESULTS:Among the participants, 57.7% were between 18 and 40 years old, 28.2% were between 41 and 60, and 14.1% were over 60. 42.1% had skin cancer before the study, 18.4% had skin cancer during the study and 89.5% stated visual deficit. The results obtained in the questionnaires showed a statistically significant difference in the physical domain, with P < 0.001.CONCLUSION:Low vision combined with skin lesions and social stigma may contribute to disturbances in the quality of life of oculocutaneous albinos. The results presented in this study demonstrated the vulnerability of the affected individuals and the special care required by those patients, at the same time that the need for further research is highlighted in order to better elucidate the aspects related to albinism.
Assuntos
Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Albinismo Oculocutâneo/psicologia , Qualidade de Vida/psicologia , Distribuição por Idade , Albinismo Oculocutâneo/fisiopatologia , Brasil , Métodos Epidemiológicos , Psicometria/métodos , Estigma Social , Fatores SociológicosRESUMO
OBJECTIVE: To evaluate the effect of strabismus surgery on nystagmus and visual acuity in patients with oculocutaneous albinism. METHODS: We conducted a non-concurrent retrospective study of 13 Puerto Rican patients with all types of oculocutaneous albinism who underwent strabismus surgery. Patients underwent genetic linkage analysis to reach a final oculocutaneous albinism classification prior to surgery. Strabismus surgery was modified by under-correction of 0.5 mm in each muscle from the standard Marshall Parks' measurements in all patients. RESULTS: Six of the 13 patients with oculocutaneous reported an improved best corrected visual acuity after surgery. Two of the 13 patients with oculocutaneous had no nystagmus following strabismus surgery. All patients were orthotropic following surgery. CONCLUSION: Strabismus surgical undercorrection may be of benefit in patients with oculocutaneous albinism.
Assuntos
Albinismo Oculocutâneo/complicações , Nistagmo Patológico/complicações , Nistagmo Patológico/cirurgia , Estrabismo/complicações , Estrabismo/cirurgia , Acuidade Visual , Adolescente , Adulto , Albinismo Oculocutâneo/fisiopatologia , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Estudos Retrospectivos , Adulto JovemRESUMO
PURPOSE: To study color vision in patients with oculocutaneous albinism (OCA) METHODS: We evaluated color vision in 42 patients with OCA using the HRR color plates. Sixty seven percent of the patients had the Hermansky-Pudlak syndrome (HPS), diagnosed genetically or clinically. The remaining patients had unknown mutations leading to OCA. RESULTS: 47.6 % of patients of OCA of all types included had a color vision defect. Of these, 55% were female and 45% were male patients. 50% of patients with the HPS (all types) had a color vision deficit. 42.9% of patients with OCA of unknown type had color weakness. 57.1% had normal color vision. CONCLUSIONS: Results suggest that many patients with OCA and the HPS have a mild red-green color perception deficiency that is not a sex linked trait. The prevalence of color vision deficits in our study population increased with decreasing visual acuity.
Assuntos
Percepção de Cores , Defeitos da Visão Cromática/etiologia , Síndrome de Hermanski-Pudlak/complicações , Adolescente , Adulto , Albinismo Oculocutâneo/classificação , Albinismo Oculocutâneo/complicações , Albinismo Oculocutâneo/fisiopatologia , Proteínas de Transporte/genética , Criança , Pré-Escolar , Percepção de Cores/genética , Defeitos da Visão Cromática/epidemiologia , Defeitos da Visão Cromática/genética , Feminino , Heterogeneidade Genética , Genótipo , Síndrome de Hermanski-Pudlak/classificação , Síndrome de Hermanski-Pudlak/genética , Síndrome de Hermanski-Pudlak/fisiopatologia , Humanos , Incidência , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Fenótipo , Estudos Prospectivos , Acuidade VisualRESUMO
PURPOSE: To study color vision in patients with oculocutaneous albinism (OCA) METHODS: We evaluated color vision in 42 patients with OCA using the HRR color plates. Sixty seven percent of the patients had the Hermansky-Pudlak syndrome (HPS), diagnosed genetically or clinically. The remaining patients had unknown mutations leading to OCA. RESULTS: 47.6 of patients of OCA of all types included had a color vision defect. Of these, 55 were female and 45 were male patients. 50 of patients with the HPS (all types) had a color vision deficit. 42.9 of patients with OCA of unknown type had color weakness. 57.1 had normal color vision. CONCLUSIONS: Results suggest that many patients with OCA and the HPS have a mild red-green color perception deficiency that is not a sex linked trait. The prevalence of color vision deficits in our study population increased with decreasing visual acuity
Assuntos
Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Humanos , Percepção de Cores , Defeitos da Visão Cromática/etiologia , Síndrome de Hermanski-Pudlak/complicações , Albinismo Oculocutâneo/classificação , Albinismo Oculocutâneo/complicações , Albinismo Oculocutâneo/fisiopatologia , Defeitos da Visão Cromática/epidemiologia , Defeitos da Visão Cromática/genética , Heterogeneidade Genética , Genótipo , Incidência , Fenótipo , Estudos Prospectivos , Percepção de Cores/genética , Proteínas de Membrana/genética , Proteínas de Transporte/genética , Síndrome de Hermanski-Pudlak/classificação , Síndrome de Hermanski-Pudlak/genética , Síndrome de Hermanski-Pudlak/fisiopatologia , Acuidade VisualRESUMO
Hermansky-Pudlak syndrome (HPS), consisting of oculocutaneous albinism and a bleeding diathesis due to the absence of platelet dense granules, displays extensive locus heterogeneity. HPS1 mutations cause HPS-1 disease, and ADTB3A mutations cause HPS-2 disease, which is known to involve abnormal intracellular vesicle formation. A third HPS-causing gene, HPS3, was recently identified on the basis of homozygosity mapping of a genetic isolate of HPS in central Puerto Rico. We now describe the clinical and molecular characteristics of eight patients with HPS-3 who are of non-Puerto Rican heritage. Five are Ashkenazi Jews; three of these are homozygous for a 1303+1G-->A splice-site mutation that causes skipping of exon 5, deleting an RsaI restriction site and decreasing the amounts of mRNA found on northern blotting. The other two are heterozygous for the 1303+1G-->A mutation and for either an 1831+2T-->G or a 2621-2A-->G splicing mutation. Of 235 anonymous Ashkenazi Jewish DNA samples, one was heterozygous for the 1303+1G-->A mutation. One seven-year-old boy of German/Swiss extraction was compound heterozygous for a 2729+1G-->C mutation, causing skipping of exon 14, and resulting in a C1329T missense (R396W), with decreased mRNA production. A 15-year-old Irish/English boy was heterozygous for an 89-bp insertion between exons 16 and 17 resulting from abnormal splicing; his fibroblast HPS3 mRNA is normal in amount but is increased in size. A 12-year-old girl of Puerto Rican and Italian background has the 3,904-bp founder deletion from central Puerto Rico on one allele. All eight patients have mild symptoms of HPS; two Jewish patients had received the diagnosis of ocular, rather than oculocutaneous, albinism. These findings expand the molecular diagnosis of HPS, provide a screening method for a mutation common among Jews, and suggest that other patients with mild hypopigmentation and decreased vision should be examined for HPS.
Assuntos
Proteínas de Transporte/genética , Síndrome de Hermanski-Pudlak/genética , Hipopigmentação/genética , Judeus/genética , Proteínas de Membrana Transportadoras , Mutação/genética , Deficiência do Pool Plaquetário/genética , Complexo 3 de Proteínas Adaptadoras , Subunidades beta do Complexo de Proteínas Adaptadoras , Albinismo Oculocutâneo/genética , Albinismo Oculocutâneo/fisiopatologia , Processamento Alternativo/genética , Sequência de Bases , Criança , Análise Mutacional de DNA , Éxons/genética , Feminino , Efeito Fundador , Síndrome de Hermanski-Pudlak/fisiopatologia , Humanos , Hipopigmentação/fisiopatologia , Peptídeos e Proteínas de Sinalização Intracelular , Íntrons/genética , Masculino , Proteínas de Membrana/genética , Dados de Sequência Molecular , Linhagem , Deficiência do Pool Plaquetário/fisiopatologia , Proteínas/genética , Porto Rico , Sítios de Splice de RNA/genética , RNA Mensageiro/análise , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Deleção de Sequência/genéticaRESUMO
The Hermansky-Pudlak Syndrome (HPS) is an autosomal recessive inherited disorder characterized by oculocutaneous albinism, tissue accumulation of ceroid pigment, and a mild to moderate bleeding diathesis attributed to storage-pool deficient (SPD) platlets. Patients have platelet aggregation and release abnormalities. In addition, low levels of plasma von Willebrand factor (vWF) antigen in some HPS patients have been associated with a greater bleeding tendency than would be predicted from either condition alone. Other HPS patients have severe bleeding despite normal levels of plasma vWF, suggesting that at least one additional factor is responsible for their bleeding diathesis. Because platelet vWF levels have been well correlated with clinical bleeding times in patients with von Willebrand's disease, we have measured the platelet vWF activity and antigen levels in 30 HPS patients and have attempted to correlate their clinical bleeding with these values. The platelet vWF activity levels in patients was significantly lower than that of normal subjects (P < 0.0001). The patients as a group also had slightly lower values of plasma vWF activity when compared with normals (P-0.03). In 11 of the HPS patients, the multimeric structure of plasma vWF showed a decrease in the high molecular weight multimers and an increase in the low molecular weight multimers. In correlating the platelet and plasma vWF values with the bleeding histories, we were not able to show a predictable relationship in the majority of the patients.
Assuntos
Albinismo Oculocutâneo/sangue , Plaquetas/metabolismo , Fator de von Willebrand/fisiologia , Trifosfato de Adenosina/metabolismo , Adolescente , Adulto , Albinismo Oculocutâneo/fisiopatologia , Tempo de Sangramento , Plaquetas/química , Criança , Pré-Escolar , Fator VIII/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Agregação Plaquetária/fisiologia , Fator Plaquetário 4/análise , Deficiência do Pool Plaquetário/sangue , Deficiência do Pool Plaquetário/fisiopatologia , Porto Rico/etnologia , beta-Tromboglobulina/análise , Fator de von Willebrand/análiseRESUMO
BACKGROUND: Hermansky-Pudlak syndrome is characterized by oculocutaneous albinism, a storage-pool deficiency, and lysosomal accumulation of ceroid lipofuscin, which causes pulmonary fibrosis and granulomatous colitis in some cases. All identified affected patients in northwest Puerto Rico are homozygous for a 16-bp duplication in exon 15 of a recently cloned gene, HPS. We compared the clinical and laboratory characteristics of these patients with those of patients without the 16-bp duplication. METHODS: Forty-nine patients -- 27 Puerto Ricans and 22 patients from the mainland United States who were not of Puerto Rican descent -- were given a diagnosis on the basis of albinism and the absence of platelet dense bodies. We used the polymerase chain reaction to determine which patients carried the 16-bp duplication. RESULTS: Twenty-five of the Puerto Rican patients were homozygous for the 16-bp duplication, whereas none of the non-Puerto Rican patients carried this mutation. Like the patients without the duplication, the patients with the 16-bp duplication had a broad variation in pigmentation. Nine of 16 adults with the duplication, but none of the 10 without it, had a diffusing capacity for carbon monoxide that was less than 80 percent of the predicted value. High-resolution computed tomography in 12 patients with the 16-bp duplication revealed minimal fibrosis in 8, moderate fibrosis in 1, severe fibrosis in 1, and no fibrosis in 2. Computed tomography in eight patients without the duplication revealed minimal fibrosis in three and no fibrosis in the rest. Inflammatory bowel disease developed in eight patients (four in each group) between 3 and 25 years of age. CONCLUSIONS: The 16-bp duplication in exon 15 of HPS, which we found only in Puerto Rican patients, is associated with a broad range of pigmentation and an increased risk of restrictive lung disease in adults.