N-acetyltransferase-2 genotypes among patients with rheumatoid arthritis attending Jordan University Hospital.
OBJECTIVE
To determine the frequency of major N-acetyltransferase (NAT2) alleles and genotypes among Jordanian patients with rheumatoid arthritis (RA).


METHODS
The study was approved by the IRB of the Jordan University Hospital. An informed consent was signed by every patient. DNA samples from 150 healthy volunteers and 108 patients with RA were analyzed by polymerase chain reaction followed by a restriction fragment length polymorphism assay (PCR-RFLP) to determine the frequency of four major alleles: NAT2*4, NAT2*5, NAT2*6, and NAT2*7.


RESULTS
The most prevalent genotypes are those that encode the slow acetylation phenotype. About 59.3% of the patients with RA carried the slow, 33.3% the intermediate, and 7.4% the fast-encoding genotypes. The frequency of NAT2 alleles was 0.241 (95% confidence interval [CI] 0.184-0.298) for NAT2*4, 0.449 (95% CI 0.383-0.515) for NAT2*5, 0.273 (95% CI 0.214-0.332) for NAT2*6, and 0.037 (95% CI 0.012-0.062) for NAT2*7 allele. The overall frequency of the slow acetylation genotype in patients with RA is similar to that in healthy Jordanian volunteers. However, the NAT2*5/7 genotype was found in seven patients (6.5%) with RA and was absent in Jordanian volunteers, and the z test revealed that the difference was statistically significant. This genotype constituted 10.9% of the genotypes encoding slow acetylation.


CONCLUSIONS
The overall acetylator genotype in RA is similar to that in healthy volunteers. The overall slow acetylator genotypes do not seem to be a genetic risk factor for RA among Jordanians. However, the NAT2*5/7 genotype seems to be related to RA. The nature of this relationship needs further clarification.
Department of Pharmacology, Faculty of Medicine, The University of Jordan, Amman, Jordan.
Muna K
MK
Oqal
Khader N
KN
Mustafa
Yacoub M
YM
Irshaid
D000107:Acetylation; D001172:Arthritis, Rheumatoid / Q000235:genetics*; D001191:Arylamine N-Acetyltransferase / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D007597:Jordan; D008297:Male; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
D001191:Arylamine N-Acetyltransferase; C478900:NAT2 protein, human