Reevaluating Usher syndrome: Transitioning from traditional subtypes to precision diagnosis

Table 1 Ocular manifestations of usher syndrome by subtype and gene involvement

Usher subtype	Causative gene(s)	Onset of visual symptoms	Ocular findings	Imaging features
USH1	MYO7A, CDH23, PCDH15	Early childhood (1st decade)	Night blindness, peripheral vision loss, nystagmus	Bone-spicule pigmentation, attenuated vessels, waxy pallor of optic disc (OCT/FAF)
USH2	USH2A, ADGRV1	Adolescence (2nd decade)	Progressive peripheral visual field loss, nyctalopia	Mid-peripheral retinal degeneration, preserved macula until late (OCT/FAF)
USH3	CLRN1	Variable (2nd-4th decade)	Late-onset RP-like changes, high inter-individual variability	Variable OCT findings; mild-moderate outer retinal thinning
Atypical USH	CEP250, CEP78, HARS, ABHD12	Adolescence-adulthood	RP-like symptoms without classical syndromic hearing loss	Macular atrophy, outer retinal loss, sometimes with foveal sparing or asymmetric loss

FAF: Fundus autofluorescence; OCT: Optical coherence tomography; RP: Retinitis pigmentosa; USH: Usher syndrome.