Characterization of the Retinal Phenotype Using Multimodal Imaging in Novel Compound Heterozygote Variants of CYP2U1.

PURPOSE: To report the retinal phenotype in 2 patients simulating type 2 macular telangiectasis with new variants in CYP2U1 implicated in hereditary spastic paraplegia type 56 (HSP 56).

DESIGN

Cross sectional case series study.

PARTICIPANTS

Five members of a non-consanguineous family (parents and 3 male children) were investigated.

METHODS

All family members underwent a full ophthalmic evaluation and multimodal retinal imaging. Two family members demonstrating retinal anomalies underwent additional OCT angiography, dual wavelength autofluorescence and fluorescence lifetime imaging ophthalmoscopy, kinetic perimetry, fundus-correlated microperimetry, electroretinography, and electro-oculography. Whole-exome sequencing was performed in all 5 family members.

MAIN OUTCOME MEASURES: To characterize the retinal phenotype in affected patients with variants in CYP2U1, using multimodal imaging: dual-wavelength autofluorescence, fluorescence lifetime, OCT angiography.

RESULTS

The 2 siblings with compound heterozygous novel variants c.452C>T; p.(Pro151Leu), c.943C>T; p.(Gln315Ter) in CYP2U1 demonstrated parafoveal loss of retinal transparency and hyperreflectivity to blue light, redistribution of macular pigment to the parafoveal edge, photoreceptor loss, and fluorescence lifetime imaging ophthalmoscopy anomalies: a pattern compatible with that seen in macular telangiectasia type 2 (MacTel). One had manifest neurological abnormalities since early childhood; the second had no neurological abnormalities. Each parent and the third sibling were heterozygous for 1 variant and were neurologically and ophthalmically normal.

CONCLUSIONS

These CYP2U1 variants are associated with a retinal phenotype very similar to that otherwise specific for MacTel, suggestive of possible links in the etiology and pathogenesis of these diseases.

FINANCIAL DISCLOSURES: The author(s) have no proprietary or commercial interest in any materials discussed in this article.