Two major spondylarthropathy phenotypes are distinguished by pattern analysis in multiplex families.
OBJECTIVE
To examine whether spondylarthropathy (SpA) disease manifestations would combine in any ordered pattern among patients from SpA multiplex families.


METHODS
SpA patients (n = 540) belonging to 190 multiplex families were thoroughly investigated. Clinical data was collected, systematic pelvic radiographs were taken, and HLA-B27 status was determined. The patterns of SpA manifestations were examined by several methods, including multiple correspondence analysis, nonhierarchical and hierarchical clustering, and discriminant analysis.


RESULTS
The nonhierarchical cluster analysis allowed us to classify patients, independent of disease duration, into 2 major groups of comparable size. Group A contained a majority of the women, whereas group B predominantly consisted of men. The 2 groups were very similar regarding axial symptoms, radiographic sacroiliitis, and uveitis. Group B was characterized by a younger age at onset and a higher frequency of clinical enthesitis, peripheral arthritis, dactylitis, psoriasis, and inflammatory bowel disease than group A. Patients belonging to those groups exhibited some degree of familial aggregation, thereby supporting their intrinsic validity.


CONCLUSIONS
Pattern analysis of SpA manifestations among familial SpA allowed us to recognize 2 main clusters independent of disease duration. Furthermore, there was a trend toward aggregation by cluster among families, suggesting that they are determined by specific genetic factors. These clusters may indeed correspond to different severity patterns.
Porcher
Raphaël
R
INSERM ERM 321, Saint-Louis Hospital, Université Denis Diderot, Paris, France.
Said-Nahal
Roula
R
D'Agostino
Maria-Antonietta
MA
Miceli-Richard
Corinne
C
Dougados
Maxime
M
Breban
Maxime
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D016000:Cluster Analysis; D016002:Discriminant Analysis; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D015796:HLA-B27 Antigen / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated; D010641:Phenotype; D025242:Spondylarthropathies / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000473:pathology*
D015796:HLA-B27 Antigen