Dutch patients with familial and sporadic ankylosing spondylitis do not differ in disease phenotype

OBJECTIVE: To assess potential differences in the phenotypic expression between familial and sporadic ankylosing spondylitis (AS). METHODS: Clinical data from the patient record forms were compared between 55 patients with AS from multicase families (i.e., families in which > or = 2 first-degree relatives have the disease) (familial AS) and 110 sex and age matched patients with AS who did not have a first-degree relative with the disease (sporadic AS). RESULTS: Between familial and sporadic AS no differences were found in age at disease onset, age at diagnosis, or prevalences of peripheral arthritis and acute anterior uveitis. CONCLUSION: Potential differences in genetic makeup are not reflected in differences in the phenotypic expression of familial and sporadic AS.