Case report: autofluorescence imaging and phenotypic variance in a sibling pair with early-onset retinal dystrophy due to defective CRB1 function.

Purpose: To phenotype two siblings with autosomal recessive early-onset retinal dystrophy due to CRB1 mutations.

Methods: Autofluorescence (AF) imaging, high resolution optical coherence tomography (OCT), and full-field electroretinography (ERG) were performed. The results of DNA sequencing from polymerase chain reaction (PCR) products of the CRB1 gene were obtained from hospital records.

Results: Two siblings, 14 years old and 17 years old, were compound heterozygotes for 749 del Ser and C948Y mutations in the gene encoding CRB1. AF imaging documented the preservation of retinal pigment epithelium (RPE) along the arterioles. High-resolution OCT showed abnormally thick retinae with increased lamination.

Conclusion: Leber congenital amaurosis caused by CRB1 is a unique form of early-onset retinal dystrophy because it spares the para-arteriolar RPE and causes abnormal retinal lamination with thickening. These findings, detectable with AF imaging and high-resolution OCT, can be combined with electrophysiology and genetic testing to molecularly classify retinal degenerations efficiently.