Macular cherry-red spot in sialidosis type 1:a case report and literature reviewOA

Sialidosis type 1 is a rare autosomal recessive lysosomal storage disorder.It is caused by mutations in the NEU1 gene,which lead to a deficiency of alpha-N-acetyl neuraminidase.This disease usually shows up in childhood or adolescence with neurological and ophthalmic symptoms.The most wellknown eye symptom is macular cherry-red spots,but there is little detailed information about eyerelated characteristics.A patient came in with reduced visual acuity,night blindness,abnormal color vision,and neurological problems.An examination of the fundus showed bilateral macular cherry-red spots,temporal optic disc pallor,and hyperautofluorescent rings around the fovea.Optical coherence tomography showed increased macular reflectivity and unclear boundaries between the ganglion cell layer and the nerve fiber layer.Fundus autofluorescence confirmed pericentral hyperautofluorescence.Microperimetry showed reduced retinal sensitivity,and visual evoked potential showed prolonged P100 latency and decreased amplitude.Genetic testing found compound heterozygous pathogenic NEU1 mutations,confirming sialidosis type 1.We also reviewed published cases.Among 85 patients,23.0%first went to ophthalmology clinics.Besides cherry-red spots,lens opacities(62.1%),nystagmus(38.2%),and optic atrophy(32.0%)were common.The c.544A>G variant was the most common one,and it was associated with higher rates of lens opacities(71.4%)and visual evoked potential abnormalities(96.4%).We report the first case of sialidosis type 1 with a comprehensive multimodal ophthalmic and genetic evaluation,as well as the first systematic review of its eye manifestations.Early and complete eye examinations,including multimodal imaging and functional assessment,are very important for timely diagnosis and management of sialidosis type 1.Clinicians should be aware that there are many eye problems associated with this disease besides cherry-red spots,such as cataract,nystagmus,and optic atrophy.