Título / Title

A PROBABLE NOVEL FBN2 VARIANT ASSOCIATED WITH AN UNCHARACTERIZED PHENOTYPE OF RETINAL DEGENERATION: A CASE REPORT

Introdução / Purpose

present a case of a probable novel variant in the FBN2 gene associated with a previously uncharacterized phenotype of retinal degeneration.

Material e Método / Methods

This study is based on a case report complemented by a comprehensive review of the literature.

Resultados / Results

The patient, a 7-year-old female, has been under investigation for nystagmus since she was 3 months old. Her mother reported that she never followed objects. The family pedigree reveals only a maternal uncle diagnosed with Osteogenesis Imperfecta, with no other family history. Upon examination, the patient presented with a best corrected visual acuity of 20/800 in the right eye and 20/1200 in the left eye, with an intraocular pressure of 18/18. Retinal evaluation revealed significant disc cupping in both eyes, slight alteration in macular pigmentation, but no retinal flecks or peripheral abnormalities. Complementary exams showed normal Autofluorescence Retinography, decreased macular response on Multierg, absence of foveal depression (fovea plana) in OCT, and a missense variant of uncertain significance (VUS) in the FBN2 gene p.(Pro.2139Ser) identified through Complete Exome sequencing. An extensive clinical evaluation was conducted to exclude Congenital Contractile Arachnodactyly.

Discussão e Conclusões / Conclusion

Given the unique presentation of this case, a literature review was conducted to understand the variability of ocular findings related to the FBN2 gene and correlate them with our case. Our review has shown that disc cupping, high myopia, and keratoconus are also observed in patients with FBN2-related dystrophy. This supports our hypothesis that this is a probable new variant. The importance of understanding different genetic tests in the face of clinical conditions that do not fit into commonly seen phenotypes is highlighted. We demonstrate the significance of clinical investigation and literature review for correct genetic counseling and how complementary tests aid in diagnosis and decision-making about the appropriate genetic test to request.

Palavras Chave

FBN2 gene , Congenital Contractile Arachnodactyly, Complete Exome sequencing

Area

CLINICAL RETINA

Institutions

instituto cearense de oftalmologia - fortaleza - Ceará - Brasil

Authors

ROBERTA HELENA PICANÇO BROWNE DE OLIVEIRA, THIAGO BARROS DE OLIVERA, GABRIELA MARTINS DE SÁ, MARCELLA FRANCO ALMEIDA, MARIANA MELO GONTIJO, PEDRO JAVIER YUGAR