Identification of five novel SLC3A1 (rBAT) gene mutations in Japanese cystinuria.
Identification of five novel SLC3A1 (rBAT) gene mutations in Japanese cystinuria.


BACKGROUND
Cystinuria is an inheritable amino aciduria and has been classified into three subtypes: I, II, and III. One of the genes responsible for cystinuria has recently been identified as SLC3A1 or rBAT, but only type I cystinuria seems to be caused by genetic alterations in rBAT. To our knowledge, thus far 38 mutations in rBAT gene have been described. In this study, we investigated rBAT mutations in Japanese patients and compared the results with the previously reported mutations in other races.


METHODS
We investigated 36 Japanese cystinuria patients by mutational analysis of rBAT gene. To identify newly mutated alleles, genomic DNA was analyzed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). When an abnormal migration was observed on SSCP, a nucleotide sequence determination was performed.


RESULTS
Five novel mutations were identified in five patients, three with missense mutations (L346P, I445T, C673R), one with a 1 bp deletion (1820delT), and one with a 2 bp insertion (1898insTA), and we detected three previously reported polymorphisms. Three of the mutations were homozygous, in whom parents had intermarried, and two were heterozygous for each mutations. Analysis of rBAT in family of the 1898insTA patient revealed that the patient had inherited the mutated allele from his parents.


CONCLUSIONS
Five novel mutations in the rBAT gene have been identified in Japanese patients with cystinuria. A racial difference was not apparent in the position and frequency of the mutations.
Egoshi
K I
KI
Department of Urology, Chiba University School of Medicine, Chiba, Japan.
Akakura
K
K
Kodama
T
T
Ito
H
H
D026923:Amino Acid Transport Systems, Basic; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003555:Cystinuria / Q000208:ethnology / Q000235:genetics*; D017931:DNA Primers; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007564:Japan; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational
D026923:Amino Acid Transport Systems, Basic; D002352:Carrier Proteins; D017931:DNA Primers; D008562:Membrane Glycoproteins; C499489:SLC7A9 protein, human