the human leukocyte antigen ( hla - b27 ) is a class i antigen of the major histocompatibility complex , and it is strongly associated with ankylosing spondylitis and other related spondyloarthropathies ( spas ) . it is present in only 8% of the general population worldwide . in the middle east , lower figures were reported from arab countries , that is , united arab emirates ( uae ) 0.5% , saudi arabia 2.6% , kuwait 4% , iraq 2.1% , lebanon 1.4% , tunisia 3.2% , and syria 1.4% [ 28 ] . on the other hand , a remarkably higher percentage was found in yemeni population ( 17% ) . in as patients , hla - b27 is present in 8095% worldwide . the prevalence of hla - b27 among as patients in the arab world is generally lower than the worldwide figure , ranging from 56 to 84% : 84% in iraq , 56% in uae , 67% in saudi arabia , 58.6% in egypt , 60% in syria , and 73.4% in iran [ 5 , 912 ] . the prevalence of hla - b27 among healthy persons and patients with as in qatar is unknown . in this study we tested 119 of as patients followed in rheumatology outpatient clinics of hamad general hospital in qatar for the status of hla - b27 . this is the first study in qatar to assess the prevalence of hla - b27 among patients with as who are residents of qatar ( locals and expatriates ) . one hundred nineteen patients with diagnosis of as who met the 1984 new york modified criteria for as were tested for hla - b27 . there were 66 arabs ( 55.5% ) , 52 asians ( 43.7% ) , and one western . among the arabs , 11 were qataris ( 9.2% ) ( 10 males and 1 female ) , 19 were jordanians / palestinians ( 15.9% ) , 10 were egyptians ( 8.4% ) , and 26 were of other arab nationalities . among the asians , 26 were indians ( 21.8% ) and 26 were of other asian nationalities for example , pakistanis , bengalis , and iranians . qatar is an arab country , in the middle east , occupying the small qatar peninsula on the northeasterly coast of the much larger arabian peninsula . of all the individuals ( 119 ) , 82 were hla - b27 positive ( 69% ) . among the arabs , 49/66 were positive ( 74% ) and among the asians 32/52 were positive ( 61% ) . positive hla - b27 was found in 9/11 qataris ( 82% ) , 14/19 jordanian / palestinians ( 72% ) , 9/10 egyptians ( 90% ) , and 19/26 indians ( 73% ) ( table 1 ) . this study was conducted to assess the prevalence of hla - b27 among patients with as living in qatar . the overall percentage was 69% and a higher prevalence was found among locals ( 82% ) . this prevalence in qataris is close to the prevalence in the west and to the prevalence reported in jordan of 75 and 81% and in iraq of 84% [ 5 , 14 , 15 ] . data from other arabian gulf countries shows that the prevalence of hla - b27 is lower . in uae , al attia found the percentage to be 56% among arabs although none of them were locals and the study sample was rather small ( 28 pts . ) . it is worth mentioning that the percentage of hla - b27 among emirian arabs is extremely low ( 0.5% ) . in saudi arabia , hla - b27 was checked in 12/15 arabs , locals comprised 6/15 , and the percentage was only 67% . in kuwait , the percentage was higher ( 77.8% ) , but kuwaitis were only 9 out of 58 . in our study the percentage in 19 jordanian patients was 72% , this was slightly lower than the findings in 2 jordanian papers , 75% in the first paper with total of 20 patients tested and 81% in the second paper with total of 52 patients tested [ 14 , 15 ] . ten egyptian patients were tested in our study and the result was positive in 9 of them ( 90% ) , which is still within the worldwide figure but much higher than the data from egypt ( 58.6% ) . our study included the asian population also , and , among 26 indians , 73% were hla - b27 positive , this is close to the frequency reported among indians in studies done in the middle east and india [ 9 , 17 ] . this is the first study to evaluate the prevalence of hla - b27 among as patients living in qatar . the results suggest that prevalence of hla - b27 among qatari patients is similar to the prevalence seen in the west . there is a lack of knowledge about the percentage of hla - b27 in healthy qataris . further studies with larger number of patients and studies that look at the prevalence of as in qatar and at the prevalence of hla - b27 in healthy qataris are needed .
background and objectives . 
 the human leukocyte antigen hla - b27 is a class 1 antigen of the major histocompatibility complex and is strongly associated with ankylosing spondylitis ( as ) . 
 the purpose of the present study is to investigate the distribution of hla - b27 in patients with as of different ethnic groups in qatar . 
 design and setting . 
 study design was cross - sectional and the setting was rheumatology clinics of hamad general hospital in qatar where most of 
 ankylosing spondylitis patients are followed up . 
 patients and methods . patients with diagnosis of as who met the new york modified criteria for as were tested for hla - b27 . 
 119 patients were tested for hla - b27 : 66 arabs , 52 asians ( indians , pakistanis , bengalis , and iranians ) , and one western ( irish ) . 
 results . of all the individuals , 
 82 were positive ( 69% ) for hla - b27 . among the arabs , 
 49/66 were positive ( 74% ) . among the asians , 32/52 were positive ( 61% ) . 
 furthermore , qatari patients ( 10 males and one female ) 9 were positive ( 82% ) , 14/19 jordanians / palestinians were positive , and 9/10 ( 90% ) egyptians were positive . among the asians , 19/26 indians were positive ( 73% ) , which was similar to the arabs . 
 conclusion . 
 hla - b27 in our small group of arabs is present in 74% . 
 comparison with other data will be presented in detail .