Juvenile Onset Ankylosing Spondylitis Research Articles

Cigarette Smoking Increases the Prevalence of Hip Joint Involvement in Ankylosing Spondylitis: A Real-World Case-Control Study.

To investigate the association between cigarette smoking and hip joint involvement in ankylosing spondylitis (AS). This case-control study compared patients with AS with and without hip involvement, as defined by the Bath Ankylosing Spondylitis Radiology Hip Index. Logistic regression analysis, subgroup analysis, and sensitivity analysis were conducted to estimate the association between smoking and hip involvement in AS. This study included 103 patients with hip involvement (cases) and 89 patients without hip involvement (controls). In univariate analysis, patients who had juvenile-onset AS (JAS), were younger, were male, had peripheral arthritis history, or had cigarette exposure were prone to hip involvement. After adjusting for confounding factors, JAS (adjusted odds ratio [aOR] 2.52, 95% CI 1.26-5.06), male sex (aOR 2.89, 95% CI 1.14-7.33), and cigarette smoking (aOR 7.23, 95% CI 2.27-23.05) were regarded to be independently associated with hip involvement in AS. Moreover, patients who smoked with exposure of less than 10 pack-years were 2.2 times more likely to have hip involvement than those without (aOR 2.21, 95% CI 1.09-4.47). This association was reproduced in subgroup analyses of males and propensity score-matched subjects, and it withstood sensitivity analysis. Smoking is a novel independent risk factor for hip involvement in AS; even exposure of less than 10 pack-years could contribute to increased prevalence of hip involvement in AS, which underlines the significance of smoking cessation in patients with AS, especially for JAS.

Midterm follow-up outcomes of total hip arthroplasty in treatment for patients with juvenile-onset ankylosing spondylitis

To assess the midterm follow-up outcomes of total hip arthroplasty (THA) for the treatment of patients with juvenile-onset ankylosing spondylitis (JAS). The clinical data of 81 patients (127 hips) with JAS (age≤16 years, JAS group) and 267 patients (391 hips) with adult onset ankylosing spondylitis (AAS) (age>16 years, AAS group) between January 2004 and March 2018 were retrospectively analysed. The baseline demographics, clinical, radiographic, and laboratory parameters were collected. Before operation and at last follow-up, the overall disease activity [Bath ankylosing spondylitis disease activity index (BASDAI)] and function status [Bath ankylosing spondylitis functional index (BASFI)], hip subjective score [Harris hip score (HHS)] and objective score [12-item short form health survey (SF-12), including physical component score (PCS) and mental component score (MCS)], and patient satisfaction for THA were reviewed. The major orthopedic complications, including periprosthetic infection, dislocation, periprosthetic fractures, and poor incision healing, were also recorded during the follow-up period. The comparison of preoperative baseline parameters showed that the body mass, body mass index, age of onset, age of surgery, disease duration, and the proportion of combined smoking history in the JAS group were significantly lower than those in the AAS group ( P<0.05), the proportion of bilateral surgeries, proportion of uveitis, proportion of combined family history, C-reactive protein, albumin, and preoperative BASFI were significantly higher than those in the AAS group ( P<0.05). Both groups were followed up. The follow-up time in the JAS group was 29-199 months, with an average of 113 months; in the AAS group was 35-199 months, with an average of 98 months. Incisions in both groups healed by first intention. During the follow-up period, there were 1 case of periprosthetic fracture, 1 case of dislocation, and 1 case of ceramic fragmentation in the JAS group, 1 case of periprosthetic infection and 6 cases of periprosthetic fracture in the AAS group. There was no significant difference in the incidence of complications between the two groups ( P>0.05). At last follow-up, the BASDAI, BASFI, SF-12 MCS, SF-12 PCS, and HHS score of the two groups were significantly improved when compared with those before operation ( P<0.05); but there was no significan difference in the difference of the above parameters before and after operation and the patient satisfaction between the two groups ( P>0.05). The midterm follow-up outcomes of THA for the treatment of JAS patients were reliable. A low age at disease onset did not exert a significant negative effect on THA reconstruction for the treatment of ankylosing spondylitis.

Risk factors for progression of juvenile-onset non-radiographic axial spondyloarthritis to juvenile-onset ankylosing spondylitis: a nested case–control study

ObjectiveTo evaluate the clinical characteristics of juvenile-onset non-radiographic axial spondyloarthritis (nr-axSpA) and to investigate risk factors associated with progression to juvenile-onset ankylosing spondylitis (JoAS).MethodsA nested case–control study was conducted using...

P011 Radiological pattern in juvenile onset Spondylarthritis differ from the adult onset spondylarthritis

Abstract Background Spondylarthritis (SpA) is a chronic inflammatory disease of the axial spine that may be affect the peripheral joints. SpA occurs predominantly in adulthood: Adult onset Ankylosing Spondylitis (AoAS). However, it can occur earlier in childhood (≤16 years old), also termed as juvenile onset Ankylosing Spondylitis (JoAS). In the second group, delay in diagnosis may lead to further structural damage. The aim of our study was to compare the differences in radiographic features between JoAS and AoAS. Methods We conducted a retrospective study in our department of rheumatology of Kassab Institute of orthopedics, including patients diagnosed with SpA according to the ASAS criteria (≥17 years at symptom onset) or to the ILAR criteria (≤16 years at symptom onset). Were not included AS patients whose disease onset was ≥ 45 years. Sociodemographic as well as disease characteristics were recorded. The lateral cervical and lumbar spine radiographs were used to assess structural damage by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and The Bath Ankylosing Radiologic Index (BASRI). The total score of mSASSS and BASRI vary between 0–72 and 0–16 respectively with higher scores indicating evolved structural damage. Radiographic features were then compared between AoAS and JoAS. The level of significance was fixed for a P &amp;lt; 0.05. Results Of 140 AS patients, 40 had JoAS and 100 had AoAS. The average age at disease onset was 12.4 ± 3 [8–16] and 25.4 ± 10.1 [17–42] respectively (P &amp;lt; 0.001). The disease duration was 10.6 years [1–44]. The average current age was 25.3 ± 10.2 [9–59] and 32.5 ± 7.5 [18–46] (P &amp;lt; 0.001). The JoAS group showed a more frequent onset with peripheral joint involvement than the AoAS group (80% vs 50%,P = 0.001). Similarly, hip involvement was more frequent among JoAS patients (57.7% vs 25%, P = 0.000). There was no significant differences between the two groups regarding the mean mSASSS score, the total BASRI score and the BASRI score for the sacroiliac joints (P = 0.9, P = 0.49, P = 0.06 respectively). Similarly, there was no differences in the mean spine BASRI score between the two groups, although there was a trend of higher scores among AoAS patients (3.2 vs 3.9, P = 0.15 respectively). On the contrary, JoAS patients had a significantly higher BASRI score for the hip than AoAS patients (2.4 vs 1.3, P = 0.000). Conclusion Our study showed that JoAS patients are more likely to suffer from early hip damage than AoAS patients. The spine BASRI was similar between the two groups despite the shorter disease duration in the juvenile group. This highlights the need for screening for hip involvement and for a closer monitoring in this subset of children.

Poor quality of life in indian ankylosing spondylitis patients

Background: Ankylosing Spondylitis (AS) is a chronic inflammatory disease that leads to significant disability. We sought to study the impact of the disease activity and functional impairment on QoL in Indian patients with AS. Methods: World Health Organization- Quality of Life-BREF (WHOQoL-BREF) questionnaire was used to measure quality of life (QoL) in 99 adults with AS (modified Rome criteria), 72 healthy individuals, and 20 rheumatoid arthritis patients. Apart from demographic variable such as age, gender, clinical manifestations, and treatment received, disease activity parameters such as duration of early morning stiffness, BASDAI, swollen and tender joint count, Erythrocyte Sedimentation Rate (ESR) and C Reactive Protein (CRP) were also recorded. Presence of damage was assessed using spinal radiographs. All values are in median (IQR). Results: Out of the 99 patients, 5 were females and 5 had juvenile onset AS. Median age was 32 (26-42) years and median disease duration was 6 (1.25-10) years. Forty-three had peripheral arthritis and 18 had enthesitis. Syndesmophytes were present on spinal radiographs in 54 cases. BASDAI correlated negatively with the physical, psychological and environmental domains (P Conclusion: Indian AS patients have poorer quality of life than patients with rheumatoid arthritis and healthy individuals, possibly due to poor control of disease activity.

Changes of serum levels of MMP-3, sRANKL, and OPG in juvenile-onset ankylosing spondylitis patients carrying different HLA-B27 subtypes.

Ankylosing spondylitis (AS) patients whose symptom onset occurs before 16 years of age are termed juvenile-onset ankylosing spondylitis (JAS). Investigations suggested that JAS had worse functional outcome, and abnormality of bone metabolism can appear in early stage of AS. The objectives of this study are to compare changes of serum inflammatory and bone metabolic markers and to explore the relationship between these biomarkers and disease activity in JAS with different HLA-B27 subtypes. Serum matrix metallopeptidase-3 (MMP-3), soluble receptor activator of nuclear factor-κB ligand (sRANKL), and osteoprotegerin (OPG) were detected by ELISA in 56, 62, and 68 JAS patients, respectively, and 32 healthy individuals were as controls. Serum MMP-3 and sRANKL were significantly higher and OPG in JAS was slightly higher than those in controls. There was no significant difference in the level of MMP-3, sRANKL, and OPG among JAS patients with B27 negativity, B*2704, B*2705, and B*2715, respectively. Serum levels of MMP-3 showed positive correlation with BASDAI and BASFI (Bath Ankylosing Spondylitis Disease Activity Index and Functional Index). Serum level of sRANKL showed positive correlation with MMP-3 and negative correlation with disease duration. The significantly higher sRANKL expression suggested the enhanced osteoclast function and imbalance of RANKL/OPG system in the inflammatory process of JAS patients carrying different B27 subtypes. It should be paid attention to the abnormality of bone metabolism during the treatment of JAS.

Clinical Features in Juvenile-Onset Ankylosing Spondylitis Patients Carrying Different B27 Subtypes.

Background. Ankylosing spondylitis (AS) is a common rheumatic disease and is characterized by inflammation of the axial skeleton. HLA-B27 is strongly associated with AS. Juvenile-onset AS (JAS) with disease onset before 16 years of age differs from adult-onset AS (AAS) in many respects. Objective. To compare the clinical features in JAS with different B27 subtypes and analyze the differences between JAS and AAS. Methods. 145 JAS and 360 AAS patients were included. The demographic data, clinical manifestations, laboratory markers, Bath AS indices, and B27 subtypes were recorded. Results. Peripheral arthritis, enthesitis, BASDAI, ESR, and CRP were significantly higher in JAS patients with HLA-B*2704 than those with B27-negative. Enthesitis and ESR were significantly higher in patients with HLA-B*2705 than those with B27-negative. The onset age of HLA-B*2715 group was much earlier than the other groups. The peripheral arthritis, enthesitis, and hip joint involvement in JAS with HLA-B*2704 were significantly higher than those in AAS with HLA-B*2704. Conclusion. JAS with different B27 subtypes had similar features in most of manifestations; JAS and AAS patients with the same subtype could have distinctive courses. Early diagnosis, hip detection, and control of systemic active inflammation in JAS patients will be helpful for improving the prognosis.

Are Indian patients with juvenile-onset ankylosing spondylitis taller than reference population ?

Background & objectives:Paucity of growth retardation has been observed by us in patients with juvenile-onset ankylosing spondylitis (JAS) in a tertiary care health centre in south India. We, therefore, undertook this pilot study to assess and compare anthropometry of patients with JAS who were 15 yr and older with that of adult onset ankylosing spondylitis (AAS) and matching Indian reference population.Methods:Consecutive male patients (December 2009- October 2012) with JAS and AAS fulfilling Modified New York Criteria were selected after applying inclusion and exclusion criteria. Demography and anthropometry were noted. Height of both patient groups as well as their parents and siblings were compared with that of the reference population. Mid-parental height and delta height were derived. Those with delta height of >8.5 cm were compared with the remaining. Multivariate logistic regression was done for variables that were found to be significant by chi-square in bivariate analysis. Similar analysis was done for BMI also.Results:There was no significant difference in anthropometric variables between JAS and AAS groups. Twenty eight of the 30 (93.33%) JAS patients were taller as compared to the reference population. Twenty six (86.67%) AAS patients were taller than the reference population. The mean heights of JAS (170.67 ± 6.94 cm) and AAS (168.2 ± 5.94 cm) patients were significantly higher than the reference value of 163.11 cm; both P<0.001. Logistic regression revealed that tallness in JAS was associated positively with hypermobility (OR=23.46,95%CI 1.2-447.2, P=0.036). No significant association was detected for height in AAS and for BMI in both JAS and AAS groups.Interpretation & conclusions:No growth retardation was seen in patients with JAS in our study. Majority of patients with JAS and AAS were taller than reference population. The difference between mean height of JAS and AAS was not significant. Larger studies involving different populations are required to confirm these findings.

SAT0368 Tumor Necrosis Factor Inhibitor Has NO Influence on Radiographic Damage in Ankylosing Spondylitis: Observation Study of Korean Spondyloarthropathy Registry (OSKAR) Data

ObjectivesTo evaluate the influence of tumor necrosis factor (TNF) blocker on the radiographic damage in ankylosing spondylitis (AS)MethodsA total of 598 TNF blocker naïve AS patients from the Observation Study...

Prevalence and risk factors of low bone mineral density in juvenile onset ankylosing spondylitis.

The objective of this study is to assess the prevalence and risk in patients with juvenile onset ankylosing spondylitis (JoAS) complicated with low bone mineral density (BMD). A total of 112 children and adolescents with JoAS were enrolled in the study. Bone mass was measured from the lumbar spine and the left proximal femur using dual-energy X-ray absorptiometry. According to the 2007 International Society of Clinical Densitometry definitions, a Z score of less than -2 was termed as "low BMD." Stepwise regression analysis was used to investigate associations between low BMD and disease-related factors including gender, age, weight, height, body mass index, disease duration, HLA-B27 antigen, grades of sacroiliitis, Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), patient global assessment (PGA), spine pain, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Low BMD was found in 18 (16.1%) cases in at least one of the two measured regions. Lumbar spine BMD had negative correlations with BASDAI, BASFI, spine pain, ESR, and CRP (P<0.05). Hip BMD significantly negatively correlated with BASDAI and PGA (P<0.05). In conclusion, patients with JoAS are likely to develop low BMD, which may be related to high disease activity.

PReS-FINAL-2185: Prognostic markers in juvenile vs. adult-onset ankylosing spondylitis

Patients experiencing ankylosing spondylitis (AS) symptoms ≤16 years-of-age are classified as juvenile-onset AS (JoAS), whilst those ≥17 years-of-age adult-onset AS (AoAS). Studies from North America, China and Turkey suggest that JoAS and AoAS patients have differing clinical characteristics and functional outcomes; although results have been inconsistent.

Gender differences in Iranian patients with ankylosing spondylitis

Inequalities in features and severity of ankylosing spondylitis (AS) have been noticed between men and women, suggesting a possible influence of gender on disease phenotypes. Comparing disease features and characterization of gender differences in clinical features and medications could help elucidate the potential influence of gender on the severity of AS in patients. This study aims to assess the influence of gender on disease patterns in Iranian patients with AS. Three hundred and twenty patients diagnosed with primary AS were assessed for demographic variables, clinical manifestations, HLA status, disease severity, functional capacities, quality of life, and treatment status. Sixty-seven women and 253 men were included corresponding to a male to female ratio of 3.78:1. Both groups were similar regarding ethnicity, positive family history, and juvenile onset AS. HLA-B27 was more frequent among males (78.3 vs. 55.2%; p < 0.001). There was a higher proportion of female patients with overall enthesitis (p < 0.05). Extra-articular manifestations and treatment modalities presented similar frequencies in both genders. No difference in gender-associated diagnostic delays was observed. Female disease was at least as severe as male disease, and in some aspects, females presented with more severe disease. Despite a relatively similar disease profile, we observed a higher rate of enthesitis among women. Together with the equally high rate of disease activity indices in both genders, these findings indicate an overall longer delay to diagnosis in our country. Early detection and specialized care would be of great practical importance.

Clinical characteristics and medical management of Iranian patients with ankylosing spondylitis

Objectives. Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease with variable clinical expression. Ethnic, racial and geographical factors have been associated with disease occurrence and expression. We intended to describe the clinical characteristics and assess the disease severity and treatment status in Iranian AS patients.Methods. A total of 320 AS patients were assessed for demographic variables, clinical manifestations, human leukocyte antigen (HLA) status, disease severity, functional capacities, quality of life and treatment status.Results. A gender ratio of 3.8:1, an average age onset of 27 ± 7.3 and a mean diagnostic delay of 8 years were observed. Eleven percent had juvenile onset AS. Positive family history was higher than that observed in most other countries. Enthesitis was a very common finding involving more than two-thirds of our patients. Uveitis was the leading extra-articular manifestation. We found an HLA-B27 prevalence of 73% and four HLA-B27 subtypes. Disease activity was high and the functional status was poor as indicated by mean Bath AS Disease Activity, Functional and Metrology indices. Quality of life was considerably impaired in our patients. We found a low percentage of patients on biological medications and a relatively higher percentage on disease modifying anti-rheumatic drugs and corticosteroids.Conclusions. Our results demonstrate a broad characterization of Iranian AS patients providing a better understanding of this disease. A national multicenter registry would enable larger- scale prospective studies to be carried out further evaluating the disease burden on patients and society.

Juvenile Versus Adult-onset Ankylosing Spondylitis — Clinical, Radiographic, and Social Outcomes. A Systematic Review

Ankylosing spondylitis (AS) has 2 main modes of onset: juvenile-onset AS (JoAS) and adult-onset AS (AoAS). It is not known whether JoAS is a subtype of AS, or AS modulated by early age of onset and longer disease duration. We performed a systematic review of the literature, identifying 12 articles and 1 abstract directly comparing JoAS and AoAS cohorts, with observational study design. Patients with JoAS appear to have more peripheral joint involvement both clinically and radiographically (especially knees and ankles) and more root joint involvement (hips and shoulders); they are more likely to proceed to hip arthroplasty and often initially present with peripheral rather than axial symptoms. Patients with AoAS appear to have more axial symptoms and radiographic disease, particularly in the lumbar spine, and worse axial metrology. In terms of other characteristics, more evidence is needed to confidently state whether JoAS and AoAS are different.

Ankylosing Spondylitis: Chinese Perspective, Clinical Phenotypes, and Associated Extra-articular Systemic Features

Ankylosing spondylitis (AS) is a common rheumatic disease in the Chinese population, which is the largest population in the world associated with the global burden of health care. Herein we review and report the epidemiology and specific clinical characteristics of Chinese AS. More than 90% of Chinese AS patients are HLA-B27 positive with the predominant HLA-B*2704 subtype; the incidence of HLA-B27 positivity ranges from 4 to 8% in the general Chinese population. The first-degree relatives of AS probands often develop atypical AS with relatively mild disease and particularly undifferentiated spondyloarthropathy in females. Chinese AS patients have higher frequencies of juvenile-onset AS and peripheral arthritis. Of extra-articular manifestations, AS patients have earlier onset and more recurrent attacks of HLA-B27-related acute anterior uveitis. Cardiac arrhythmias or other cardiovascular disorders and metabolic syndrome are not infrequently found. Importantly, apical lung diseases in Chinese AS patients are also frequently associated with tuberculosis infection.

FRI0435 Prognostic markers in juvenile vs. adult-onset ankylosing spondylitis.

BackgroundPatients experiencing ankylosing spondylitis (AS) symptoms ≤16 years-of-age are classified as juvenileonset AS (JoAS), whilst those ≥17 years-of-age as adult-onset AS (AoAS). Studies from North America, China and Turkey suggest...

FRI0298 Differences between juvenile and adult-onset ankylosing spondylitis in moroccan patients

ObjectivesWe aimed to assess differences between juvenile-onset ankylosing spondylitis (JOAS) and adult-onset ankylosing spondylitis (AOAS) in terms of activity, severity and quality of life (QoL) in Moroccan patients.MethodsIn this cross-sectional...

AB0902 Different clinical expression of patients with ankylosing spondyloarthritis by sex according the time of evolution. Regisponser data

BackgroundIt’s a potentially serious illness that can cause significant functional disability and ultimately axial fusion.Historically it has been considered a disease that mainly affects men,but recent studies have shown that...

Clinical, Functional, and Radiographic Differences Among Juvenile-onset, Adult-onset, and Late-onset Ankylosing Spondylitis

The aim of our study was to compare the clinical, functional, and radiographic outcomes at different ages of onset in patients with ankylosing spondylitis (AS). A total of 546 patients were enrolled consecutively and classified into 3 groups based on their age at symptom onset: (1) juvenile-onset AS (age ≤ 16 years; JoAS); (2) adult-onset AS (> 16 but < 40 years; AoAS); and (3) late-onset AS (≥ 40 years; LoAS). We compared the differences among the 3 groups. OR for disease outcomes were calculated and adjusted for sex, HLA-B27, and disease duration. There were 67 patients (12.3%) with JoAS, 460 (84.2%) with AoAS, and 19 (3.5%) with LoAS. Male sex and HLA-B27 were associated with a younger age at onset (p < 0.001). Compared to patients with AoAS, patients with JoAS were more likely to present with peripheral arthritis, while patients with JoAS and LoAS were less likely to have back pain at the onset of AS (p < 0.05). After controlling for multiple covariates, JoAS was found to be associated with a worse functional outcome and global assessment, and a high serum immunoglobulin A level (p < 0.05). Patients with JoAS had less lumbar spinal radiographic severity (p < 0.05). There were no statistical differences in clinical or functional outcome between the LoAS and AoAS groups. None of the LoAS patients had radiographic hip involvement. Sex and HLA-B27 are significantly associated with age at onset of AS. Both JoAS and LoAS have their distinctive symptoms/signs at onset and different disease outcomes.

Registry of the clinical characteristics of spondyloarthritis in a cohort of Egyptian population

The aim of this study was to characterize the socioeconomic features, as well as disease activity and functional status, treatment use, and quality of life in a cohort of Egyptian population. All are measured by standard instruments. This is a descriptive multicenter; cross-sectional study included consecutive patients with spondyloarthritis (SpAs) diagnosed according to the European spondyloarthritis study group criteria. Four Egyptian centers participated (one from the Upper Egypt, one from the Delta, and two from the West Coast), all adopted the same criteria for patient assessment, and data were collected in the same data base over a 12-month duration. A total of 75 patients were included in the study. The series consisted of 34 ankylosing spondylitis (AS) patients (64%), 23 patients with psoriatic arthritis (45.3%), 15 patients with Juvenile onset AS (18.7%), 2 patients with reactive arthritis (2.7%), and one with inflammatory bowel disease-related arthritis (1.3%). There was predominance of male patients (84%). All were Caucasians; 13% from the Upper Egypt, and 87% from the Delta and West coast Egypt. Their mean age was 37.44 ± 12.8 years; mean disease duration was 11.85 ± 9.27 years. Pure axial disease was reported by 24% of the patients, and pure peripheral involvement was observed in 4%, while the mixed pattern (axial, peripheral, and entheseal) was observed in 34%. Dactylitis was detected in 9.3%, tarsitis in 8%, and enthesitis in 29.3%. The most common extra-articular manifestation was anterior uveitis, reported by 5.3% of patients. Human leukocytic antigen B27 (HLA-B27) was positive in 58.7% of the tested patients (n = 29). Mean Bath Ankylosing Spondylitis Disease activity Index (BASDAI) score was 4.16 ± 2.12, of which 22 patients had a score more than 4; mean Bath Ankylosing Spondylitis Functional Index 5.12 ± 2.40, mean BASMI 4.17 ± 2.95, mean BAS-GI 5.92 ± 2.00, and mean Health assessment questionnaire 1.10 ± 0.65. In addition, patients with AS showed a higher incapacity for work, felt more pain and presented more axial affection than others. The most utilized treatments were the conventional drugs including non-steroidal anti-inflammatory drugs, followed by sulfasalazine (50%), methotrexate (14%), and steroids (6%). Tumor necrosis factor-alpha inhibitors were received by 7 patients (14%), mostly in the form of Infliximab (85.7%) and were used by only 38.7% of patients with BASDAI of 4 or more. This registry provides the first clinical and demographic data of SpA patients in Egypt upon which a large-scale database registration can be initiated. The most frequently diagnosed SpA in Egyptian patients was AS, with mainly combined axial and peripheral involvement. The clinical spectrum of SpAs seen among Egyptians is similar to most other registries; however, Egyptian AS patients showed some differences in the clinical manifestations. The low frequency of HLA-B27 and the clinical variations in AS may be due to different genetic and/or environmental factors in Egypt.