Heterozygous structural variation mimicking homozygous missense mutations in NEU1 associated with presenting clinical signs in eyes alone.

The results of this case remind us of the limitations of routine exome sequencing and the need to perform segregation studies and deletion/duplication analysis or WGS if parental studies do not support exome findings. In addition, patients with sialidosis may present with ocular manifestations without systemic signs early in the disease course.