engleski

Frequency of arylsulfatase A pseudodeficiency mutations in patients with diagnosis of cerebral palsy

Arylsulfatase A (ASA, EC 3.1.6.1) is a lysosomal enzyme involved in sulfatide catabolism. In the central nervous system, sulfatides represent a major lipid constituent of oligodendrocyte membranes, and contribute to maintenance of myelin sheath integrity. Deficiency of ASA causes metachromatic leukodystrophy, rare autosomal recessive disorder characterized by the storage of cerebroside sulfate mainly in the nervous tissue. Low ASA activities have been also reported in healthy individuals and several neurologic and psychiatric disorders, due to condition termed ASA pseudodeficiency. Two mutations in the ASA gene, responsible for the majority of pseudodeficiency alleles, are designated as N350S and 1524+95 A›G mutation. Frequency of the mutations associated with ASA pseudodeficiency in the Croatian population has been estimated at 6.8 % for N350S and 2.8 % for 1524+95 A›G mutation. The aim of this preliminary study was to establish the frequency of both previously described ASA pseudodeficiency mutations in 48 patients with diagnosis of spastic form of cerebral palsy. For this purpose, genomic DNA was extracted from leukocytes and two fragments of ASA gene were amplified using specific primers. After digestion with adequate restriction enzymes, the reaction products were analyzed by electrophoresis on 2-3 % agarose gel. In addition, the activity of arylsulfatase A was determined by spectrophotometry using p-nitrocatechol sulfate as chromogenic substrate. In analyzed group of patients we found 9 heterozygous carriers of N350S mutation and 8 heterozygous carriers of 1524+95 A›G mutation. The frequency of mutated alleles was thus estimated at 9.37 % (9 of 96 alleles) and 8.33 % (8 of 96 alleles) for N350S and 1524+95 A›G mutation, respectively. In conclusion, our preliminary results show that the frequency of both mutations responsible for arylsulfatase A pseudodeficiency is higher in patients suffering from spastic cerebral palsy in comparison with healthy population.

arylsulfatase A; pseudodeficiency mutations; cerebral palsy; Croatian population

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