RESUMO
Background: The clinical phenotyping of patients with achromatopsia harboring variants in phosphordiesterase 6C (PDE6C) has poorly been described in the literature. PDE6C encodes the catalytic subunit of the cone phosphodiesterase, which hydrolyzes the cyclic guanosine monophosphate that proceeds with the hyperpolarization of photoreceptor cell membranes, as the final step of the phototransduction cascade. Methods: In the current study, two patients from a consanguineous family underwent full ophthalmologic examination and molecular investigations including WES. The impact of the variant on the functionality of the protein has been analyzed using in silico molecular modeling. Results: The patients identified with achromatopsia segregated a homozygous missense variant (c.C1775A:p.A592D) in PDE6C gene located on chromosome 10q23. Molecular modeling demonstrated that the variant would cause a protein conformational change and result in reduced phosphodiesterase activity. Conclusion: Our data extended the phenotypic spectrum of retinal disorders caused by PDE6C variants and provided new clinical and genetic information on achromatopsia.
Assuntos
Alelos , Defeitos da Visão Cromática/genética , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/genética , Proteínas do Olho/genética , Mutação de Sentido Incorreto/genética , Adulto , Sequência de Bases , Defeitos da Visão Cromática/fisiopatologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/química , Eletrorretinografia , Proteínas do Olho/química , Feminino , Humanos , Masculino , Modelos Moleculares , LinhagemRESUMO
A 13-year-old boy was referred because of visual deterioration in his right eye. The visual acuity was two meters of counting fingers. Indirect ophthalmoscopy and biomicroscopy revealed exudative macular edema as well as tumor-like telangiectatic vessels and exudation in temporal periphery. With diagnosis of Coats' disease (stage II) confirmed by fluorescein angiography, three intravitreal injections of bevacizumab were performed at 6-week intervals. One year after the last injection, there was a significant resolution of macular edema as well as visual acuity improvement to 20/20. This is the first case report in which a distinct improvement in macular edema was observed with intravitreal bevacizumab in Coats' disease.
