Association of a new allele of the TAP2 gene, TAP2*Bky2 (Val577), with susceptibility to Sjögren's syndrome.
OBJECTIVE
To investigate the polymorphisms of TAP (transporters associated with antigen processing) genes among patients with primary Sjögren's syndrome (SS) in order to clarify the potential association of the polymorphisms with disease susceptibility.


METHODS
Polymorphisms of the TAP1 and TAP2 genes in 108 Japanese SS patients were determined by analyzing TAP genes using the polymerase chain reaction-single-stranded conformation polymorphism technique.


RESULTS
The allelic frequency of the TAP1 gene was not significantly different between SS patients and normal subjects. In addition to all known TAP2 alleles, a new allele (Bky2), which had a unique substitution at codon 577 (ATG-->GTG: Met-->Val), was identified in both groups. The allelic frequency of Bky2 was significantly higher in SS patients (12.0%) than in normal subjects (5.1%) (P < 0.05). Moreover, a significantly greater frequency of SS-A antibody was found among SS patients with Bky2 (18 of 23; 78%) than among those without Bky2 (33 of 85; 39%) (P = 0.001).


CONCLUSIONS
The mutation in TAP2 (Val577) may be involved in SS-A autoantibody production and could be a genetic factor that determines susceptibility to SS.
Kumagai
S
S
Kobe University Medical School, Japan.
Kanagawa
S
S
Morinobu
A
A
Takada
M
M
Nakamura
K
K
Sugai
S
S
Maruya
E
E
Saji
H
H
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000483:Alleles; D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D005787:Gene Frequency; D005796:Genes; D020022:Genetic Predisposition to Disease; D006801:Humans; D008285:Major Histocompatibility Complex / Q000235:genetics; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012859:Sjogren's Syndrome / Q000235:genetics* / Q000276:immunology / Q000473:pathology
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D001323:Autoantibodies; D017931:DNA Primers; C073119:TAP1 protein, human; C071692:TAP2 protein, human