Clinical and biochemical study of 29 Brazilian patients with metachromatic leukodystrophy.

Metachromatic leukodystrophy (MLD) is a lysosomal disorder caused by arylsulfatase A (ARSA) deficiency. It is classified into three forms according to the age of onset of symptoms (late infantile, juvenile, and adult). We carried out a cross-sectional and retrospective study, which aimed to determine the epidemiological, clinical, and biochemical profile of MLD patients from a national reference center for Inborn Errors of Metabolism in Brazil. Twenty-nine patients (male, 17) agreed to participate in the study (late infantile form: 22; juvenile form: 4; adult form: 1; asymptomatic: 2). Mean ages at onset of symptoms and at biochemical diagnosis were, respectively, 19 and 39 months for late infantile form and 84.7 and 161.2 months for juvenile form. The most frequently reported first clinical symptom/sign of the disease was gait disturbance and other motor abnormalities (72.7%) for late infantile form and behavioral and cognitive alterations (50%) for juvenile form. Leukocyte ARSA activity level did not present significant correlation with the age of onset of symptoms (r = -0.09, p = 0.67). Occipital white matter and basal nuclei abnormalities were not found in patients with the late infantile MLD. Our results suggest that there is a considerable delay between the age of onset of signs and symptoms and the diagnosis of MLD in Brazil. Correlation between ARSA activity and MLD clinical form was not found. Further studies on the epidemiology and natural history of this disease with larger samples are needed, especially now when specific treatments should be available in the near future.

Early manifestations of multiple sulfatase deficiency.

We describe two boys, presenting by 1 year of age, with developmental delay from birth, mildly coarse facial features, and hepatomegaly. These clinical features were most suggestive of a mucopolysaccharidosis, particularly MPS II. Biochemical studies, including sulfate incorporation in fibroblasts and lysosomal enzyme analyses in fibroblasts, leukocytes, and serum, showed abnormalities in both sulfatide and mucopolysaccharide metabolism and led to the diagnosis of multiple sulfatase deficiency. With time, both patients developed an ichthyotic rash and profound intellectual deterioration. We conclude that findings in the first year of life in some patients with MSD may closely resemble those in patients with a MPS disorder rather than the late infantile form of metachromatic leukodystrophy, as is classically described. Thus, MSD should be considered in the young patient suspected of having a MPS disorder.