A 9-bp deletion (2320del9) on the background of the arylsulfatase A pseudodeficiency allele in a metachromatic leukodystrophy patient and in a patient with nonprogressive neurological symptoms.
A 9-bp deletion (2320del9) was detected in the arylsulfatase A genes of a patient with late infantile metachromatic leukodystrophy and of a patient with nonprogressive neurological symptoms and very low arylsulfatase A activity. Both patients are heterozygous for the deletion, which involves codons 406-408 and causes loss of a Ser-Asp-Thr tract in the predicted protein. In both patients the 9-bp deletion lies in a pseudodeficiency allele. The patient with metachromatic leukodystrophy carries the common 459 + 1G > A mutation in the other allele. The other patient is homozygous for the pseudodeficiency allele, and consequently is a compound heterozygote for a metachromatic leukodystrophy allele and a pseudodeficiency allele. We hypothesize that the compound heterozygosity predisposes to the development of nonprogressive neurological symptoms in the presence of additional, still unknown, genetic or nongenetic factors.
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Laboratorio di Diagnosi Pre e Postnatale di Malattie Metaboliche, Istituto G. Gaslini-Largo G. Gaslini 5, Genoa, Italy.
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Stroppiano
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Corsolini
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Caroli
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Gatti
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D000483:Alleles; D002553:Cerebroside-Sulfatase / Q000172:deficiency* / Q000235:genetics*; D002648:Child; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000201:enzymology / Q000235:genetics; D007966:Leukodystrophy, Metachromatic / Q000201:enzymology / Q000235:genetics*; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D017384:Sequence Deletion
D002553:Cerebroside-Sulfatase