Case Report: Multimodal optical imaging and genetic features of AB variant GM2 gangliosidosis

A seven-month-old Chinese girl presented to the hospital with nystagmus for 2 months. The family history was negative, and the parents were not known to be consanguineous. Fundus photography showed a cherry-red spot with a ring of whitish infiltrate surrounding both macula. Fundus fluorescein angiography showed normal retinal circulation and vessels. Optical coherence tomography (OCT) revealed thickening and increased reflectivity of the inner retinal layers with a shadowing effect on outer structures. The patient had no obvious neurological symptoms, and the MRI of the head was normal. The exome genome sequencing results showed that there was homozygous deletion (chr5: 150639196-150639548) of exon 2 in the GM2A gene. Finally, the patient was diagnosed with AB variant GM2 gangliosidosis.