TY - JOUR
T1 - Contribution of arylsulfatase A mutations located on the same allele to enzyme activity reduction and metachromatic leukodystrophy severity
AU - Regis, Stefano
AU - Corsolini, Fabio
AU - Stroppiano, Marina
AU - Cusano, Roberto
AU - Filocamo, Mirella
PY - 2002/4
Y1 - 2002/4
N2 - The occurrence of different mutations on the same arylsulfatase A allele is not uncommon, due to the high frequency of several variants, among which the pseudodeficiency mutations are particularly important. We identified a late infantile metachromatic leukodystrophy patient carrying on one allele the new E253K mutation and the known T391S polymorphism, and on the other allele the common P426L mutation, usually associated with the adult or juvenile form of the disease, and the N350S and *96A>G pseudodeficiency mutations. To analyze the contribution of mutations located on the same allele to enzyme activity reduction, as well as the possible phenotype implications, we performed transient expression experiments using arylsulfatase A cDNAs carrying the identified mutations separately and in combination. Our results indicate that mutants containing multiple mutations cause a greater reduction of ARSA activity than do the corresponding single mutants, the total deficiency likely corresponding to the sum of the reductions attributed to each mutation. Consequently, each mutation may contribute to ARSA activity reduction, and, therefore, to the degree of disease severity. This is particularly important for the alleles containing a disease-causing mutation and the pseudodeficiency mutations: in these alleles pseudodeficiency could play a role in affecting the clinical phenotype.
AB - The occurrence of different mutations on the same arylsulfatase A allele is not uncommon, due to the high frequency of several variants, among which the pseudodeficiency mutations are particularly important. We identified a late infantile metachromatic leukodystrophy patient carrying on one allele the new E253K mutation and the known T391S polymorphism, and on the other allele the common P426L mutation, usually associated with the adult or juvenile form of the disease, and the N350S and *96A>G pseudodeficiency mutations. To analyze the contribution of mutations located on the same allele to enzyme activity reduction, as well as the possible phenotype implications, we performed transient expression experiments using arylsulfatase A cDNAs carrying the identified mutations separately and in combination. Our results indicate that mutants containing multiple mutations cause a greater reduction of ARSA activity than do the corresponding single mutants, the total deficiency likely corresponding to the sum of the reductions attributed to each mutation. Consequently, each mutation may contribute to ARSA activity reduction, and, therefore, to the degree of disease severity. This is particularly important for the alleles containing a disease-causing mutation and the pseudodeficiency mutations: in these alleles pseudodeficiency could play a role in affecting the clinical phenotype.
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U2 - 10.1007/s00439-002-0701-y
DO - 10.1007/s00439-002-0701-y
M3 - Article
C2 - 11941485
AN - SCOPUS:0036556249
VL - 110
SP - 351
EP - 355
JO - Human Genetics
JF - Human Genetics
SN - 0340-6717
IS - 4
ER -