A 3′ splice site consensus sequence mutation in the intron 3 of the α-galactosidase a gene in a patient with Fabry disease

Fabry disease is an X-linked disorder accompanied with accumulation of glycosphingolipids resulting from the deficient activity of the lysosomal hydrolase, α-galactosidase A (α-GalA). In the present study, mRNA for α-GalA in fibroblasts from an 11-year-old Japanese patient with Fabry disease was examined using the reverse transcriptase-polymerase chain reaction (PCR). The shorter message of α-GalA was demonstrated in this patient when compared with the normal control. The complete deletion of exon 4 in the mRNA for α-GalA in the patient was disclosed by analysis of cDNA with restriction enzyme digestion and asymmetrical PCR sequencing. The direct sequencing of the genomic DNA demonstrated a single base substitution (G→A) at the 3′ end of the consensus sequence of intron 3. This mutation destroyed a splice site in the α-GalA, which produced a mutant allele. It was also shown that the mother of the patient had this mutant as well as normal alleles as a heterozygote.