Macular cherry-red spot helps diagnose rare storage disorder in an infant with repeated respiratory tract infections: case report.

A seven-month-old male child was brought in for an eye test for poor vision and nystagmus noticed from four months of age. The child had delayed milestones of development and multiple (six times) episodes of unexplained lower respiratory tract infection (from two months of age) treated by pediatricians at different centers without complete cure. Fundus examination showed bilateral cherry-red spots at the macula. There were diffusely distributed hyper-pigmented patches (Mongolian spots) on the back and extensor aspect of the extremities. The case was sent back to the pediatricians for a re-evaluation to rule out storage disorder. Lysosomal enzyme assay in the leucocytes showed a significantly reduced β-galactosidase level (15.6 nmol/hr/mg protein in contrast to a normal range of 79.6 to 480.0). This confirmed the patient to be a case of lysosomal storage disease, the GM1 gangliosidosis (type I).