The affected individuals in our cohort are all siblings with healthy parents (no history of consanguinity), with 5 of 12 progeny having IFH (Figure 1). Of the 12 siblings, 7 were male and 5 were female. Of the 5 with IFH, 4 were male and 1 was female. All 5 affected members manifested decreased visual acuity (mean, 0.82 logMAR; visual acuities of affected siblings were 20/100 OU in sibling 1, 20/70 OU in sibling 4, 20/70 ODand 20/100 OS in sibling 6, 20/80 OD and 20/100 OS in sibling 8, and counting fingers at 3 ft OU in sibling 10), pendular nystagmus with variable null points in each affected individual, low to moderate hyperopia (mean hyperopia, 3.3 diopters), dark hair color, normal anterior segment on slitlamp examination, and absent iris transillumination defects. Dilated retinal examinations of each of the affected individuals revealed normal optic discs, absent foveal depression, absent foveal pit, and a normal retinal periphery (Figure 2). Multifocal electroretinographic results were normal in both affected and unaffected family members. Imaging with SD-OCT (Cirrus high-definition OCT; Carl Zeiss Meditec) in all 5 affected siblings demonstrated absent foveal depression, absence of extrusion of plexiform layers, absence of outer segment lengthening, and absence of outer nuclear layer widening, all features corresponding to grade 4 foveal hypoplasia as described by Thomas et al2 (Figure 3, Figure 4, , and ). Imaging with SD-OCT in the unaffected siblings demonstrated normal foveal anatomy. Mutation analysis for PAX6 was performed on saliva samples of both affected and unaffected siblings (Oragene DNA kit; DNA Genotek Inc). No PAX6 mutation was found.