Association of myasthenia gravis with polymorphisms in the gene of histamine N-methyltransferase.
BACKGROUND
Histamine N-methyltransferase (HNMT) is the main metabolizing enzyme of histamine. Histamine modulates immune responses and plays a role in the pathogenesis of autoimmune disorders.


METHODS
The non-synonymous HNMT C314T polymorphism and the A939G single-nucleotide polymorphism (SNP) influencing HNMT mRNA stability were genotyped in 213 patients with myasthenia gravis (MG) and 342 healthy controls.


RESULTS
The carrier frequency of the A allele of the A939G SNP was over-represented among patients with anti-AchR and anti-Titin antibodies (P = 0.05 and P = 0.004, respectively); the presence of the minor G allele was protective against anti-AchR and anti-Titin positive MG (OR = 0.67 and OR = 0.54, respectively). The combination of the G allele carrier status with wild-type C314C homozygosity was also protective against MG (OR = 0.55, P = 0.008) and against the development of anti-AchR antibodies (OR = 0.37, P = 0.01).


CONCLUSIONS
The A939G HNMT polymorphism is associated with autoimmune MG, while no association with C314T SNP was found.
Division of Clinical and Experimental Neuroimmunology, Department of Neurology, University of Pecs, Pecs, Hungary.
Blanka
B
Kellermayer
Noemi
N
Polgar
Jozsef
J
Pal
Miklos
M
Banati
Anita
A
Maasz
Peter
P
Kisfali
Zsolt
Z
Hosszu
Annamaria
A
Juhasz
Henrik Boye
HB
Jensen
Attila
A
Tordai
Csilla
C
Rozsa
Bela
B
Melegh
Zsolt
Z
Illes
D000328:Adult; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D005838:Genotype; D006637:Histamine N-Methyltransferase / Q000235:genetics*; D006801:Humans; D006814:Hungary; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000235:genetics*; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D020871:RNA Stability
D006637:Histamine N-Methyltransferase