Bosch-Boonstra-Schaaf Syndrome

The following case review presents a 3-year-old, born full term, with developmental delay which was referred by an outside physician for further evaluation. Further testing was required for a final diagnosis which included an MRI of the brain and genetic testing. Results: The patient presented after an outside referral at age 3. The child had already been diagnosed by her pediatrician with developmental delay including speech, motor and cognitive delay. Due to her nystagmus, she was referred to BPEI for further evaluation. On clinical exam she showed mild amblyopia for her age (tested with Teller acuity cards due to speech delay) and with low symmetric bilateral hyperopia. She showed only latent conjugate jerk nystagmus on ocular occlusion, which was horizontal, binocular with a fast phase towards the uncovered eye. No deviation was noted at distance and the cover/uncover test showed a small angle intermittent esotropia. The anterior segment revealed no pathology and the dilated exam showed mild bilateral optic nerve pallor with present foveal reflex. Neuro-Ophthalmology consult requested a brain/orbits MRI with unremarkable findings. At this time a hereditary atrophy was suspected requiring genetic testing which revealed a heterozygous pathogenic variant in NRF21 gene associated with Bosch-Boonstra-Schaaf optic neuropathy. 

Bosch-Boonstra-Schaaf is an autosomal dominant condition characterized by visual impairment, optic atrophy, developmental delay and intellectual disability. Other common features described in affected individuals include hypotonia, thinning of the corpus callosum, autism spectrum disorders and other behavioral features. It was first described in 2014 and since then less than 50 cases have been reported in the literature. Although the spectrum of phenotypes is variable, ophthalmological involvement with variable optic nerve atrophy is a key feature of this disease.

Presentation Date: 08/13/2020

Issue Date: 01/22/2021