Here, we found that pathogenic and protective mutations in arylsulfatase A (ARSA), a gene responsible for metachromatic leukodystrophy, a lysosomal storage disorder, are linked to Parkinson's disease.
We studied the coupled Sap B-ASA reaction in vitro using detergent-free micellar and liposomal assay systems and in vivo using cell culture models of metachromatic leukodystrophy.
A family exhibiting a leukocytic arylsulfatase A deficiency, probably inherited in an autosomal recessive manner, differed from patients with typical metachromatic leukodystrophy in that sulfatiduria was absent and there was readily detectable cerebroside sulfatase activity.
To bypass the BBB, we infused recombinant human ASA (rhASA) by implanted miniature pumps into the cerebrospinal fluid (CSF) of a conventional and a novel, genetically aggravated ASA knockout mouse model of MLD. rhASA continuously delivered to the lateral ventricle for 4 weeks penetrated the brain parenchyma and was targeted to the lysosomes of brain cells.
The identification of MLD patients who are homozygous for the ASA-PD allele has brought about the need to re-evaluate the allele in light of the possible role that it may play in the development and progression of disease.
In addition, the presence of the most common mutations associated with ASA pseudo-deficiency (N350S, 1524+95 A>G) and metachromatic leukodystrophy (P426L) was detected in all investigated patients.
Prosaposin (PSAP) gene mutations, affecting saposin B (Sap-B) domain, cause a rare metachromatic leukodystrophy (MLD) variant in which arylsulfatase A (ARSA) activity is normal.
Our data indicate that neural precursors generated via reprogramming from MLD patients can be engineered to ameliorate sulfatide accumulation and may thus serve as autologous cell-based vehicle for continuous ARSA supply in MLD-affected brain tissue.
The diagnosis of metachromatic leukodystrophy (MLD) was confirmed by the finding of low arylsulfatase A (ASA) levels in cultured fibroblasts in both sisters.
In the absence of direct demonstration of deficiency, other types of evidence were needed to support the premise that the genetic defect was not associated with the arylsulfatase A locus as in classical MLD.
Our work, which reports the largest series of patients with sphingolipid activator protein B deficiency, suggests that this variant is likely to be more common than arylsulfatase A-deficient metachromatic leukodystrophy in Arabs, a notion that has potential diagnostic and preventive implications.
The inherited deficiency of arylsulfatase A (ASA) in humans causes lysosomal accumulation of sulfatides in visceral organs and in the nervous system and leads to wide-spread demyelination (metachromatic leukodystrophy, MLD).