Ocular findings in metachromatic leukodystrophy. An electron microscopic and enzyme study in different clinical and genetic variants.

Histopathological studies of the eyes from three patients affected with the infantile form of metachromatic leukodystrophy (MLD) showed the storage of metachromatic complex lipids in the retinal ganglion cells, in the optic nerve and the ciliary nerves, as well as the storage of a mucopolysaccharide-like material in the nonpigmented epithelium of the ciliary body. The lesions were limited to the optic, ciliary, and sensory nerves in a fourth patient with the juvenile form of the disorder. These morphological aspects, which are probably related to differences in sulfatase A activities, may explain the variability of the ocular manifestations in metachromatic leukodystrophy. Seven children affected with infantile MLD or with mucosulfatidosis were examined by conjunctival biopsy. Typical lesions of the sensory nerves were obvious and allowed the diagnosis of the disease. However, it seemed impossible to separate the different forms by histopathological studies only. The tear enzymes were assayed in most of the cases and demonstrated a profound deficiency of arylsulfatase A, or of arylsulfatase A and B, in the classical MLD and in mucosulfatidosis, respectively.