Mucolipidosis type IV in a child

Mucolipidosis type IV is a rare autosomal recessive lysosomal storage disorder with psychomotor developmental delay, visual impairment, and achlorhydria. A mutation in the MCOLN1 gene causes an alteration of the protein mucolipin-1 that results in the accumulation of lipids and proteins in cytoplasmic vacuoles derived from lysosomes. Visual impairment results mainly from corneal clouding and retinal degeneration. The involvement of the corneal epithelium has been proposed following clinical observation and confirmed by ultrastructural studies of the cornea. We present the case of a child of French Canadian origin affected by mucolipidosis type IV who showed abnormal optical coherence tomography imaging of the cornea, typical skin cell inclusions on electronic microscopy, and a novel pathogenic mutation.