The second Japanese family with Malattia Leventinese/Doyne honeycomb retinal dystrophy

Purpose To describe the clinical and genetic findings of patients in the second Japanese family with Malattia Leventinese/Doyne honeycomb retinal dystrophy (ML/DHRD). Methods Two patients (a 41-year-old male proband and his third son) underwent comprehensive ophthalmic examinations, including full-field and multifocal electroretinography (ERG). Sanger sequencing was performed to detect an EFEMP1 gene variant (p.Arg345Trp), which was identified as the only causative pathogenic variant. Results Genetic analysis revealed that both patients carried the heterozygous variant, but the other unaffected family members did not. Although the proband exhibited innumerable radially distributed drusen in both the posterior poles and good visual acuity at initial presentation, bilateral choroidal neovascularization (CNV) developed during the 15-year follow-up. The proband received 15 intravitreal anti-vascular endothelial growth factor (VEGF) injections in the left eye (LE) and two injections in the right eye (RE). At 56 years of age, his decimal best-corrected visual acuity was 0.1 and 1.2 in the LE and RE, respectively. Full-field ERG showed that while the rod and combined responses were within normal amplitudes, the cone and 30-Hz flicker responses had slightly decreased amplitudes. Multifocal ERG revealed attenuated central responses in the LE and decreased temporal responses in the RE. In the 20-year-old son, multifocal ERG showed normal responses in both eyes. Conclusion This is the first report of ML/DHRD in a patient who developed bilateral CNV and received anti-VEGF treatment in both eyes. Although multifocal ERG exhibited worsening of macular function, the generalized photoreceptor function was preserved until middle age.