Gout in black South Africans: a clinical and genetic study.

OBJECTIVE: To define the clinical characteristics of gout and determine if there were any genetic associations with gout in black South Africans. METHODS: The records of 107 patients with gout seen over a five year period were retrospectively analysed. The HLA class I and class II antigens were studied in a prospective survey of 46 patients. RESULTS: The male to female ratio was 6.6:1. The diagnosis of gout was based on identification of monosodium urate crystals from the synovial fluid, synovial tissue or tophaceous material in 62 patients (58%) and on clinical criteria in the remaining 45 patients (42%). The mode of presentation was monoarthritis in 40 patients (37.4%), pauciarthritis in 30 (28%) and polyarthritis in 37 (34.6%). The joints which were most frequently involved were the knee in 91 patients (85%), the first metatarsophalangeal in 80 (74.8%) and the ankle in 66 (61.7%). A secondary cause was identified in 52 patients (48.6%) (diuretic therapy in 48 patients and chronic renal impairment in four); 55 patients (51.4%) had primary gout. The genetic study showed an increased frequency of HLA-B14 in patients with primary gout compared with controls. CONCLUSIONS: Gout is more common in black Africans than previously recognised and frequently presents with involvement of more than one joint. There was an increased frequency of HLA-B14 in patients with primary gout but the clinical significance of this is uncertain.

HLA-B27-associated seronegative enthesopathy and arthropathy in a black child.

A 16-year-old black child with seronegative enthesopathy and arthropathy, who had the HLA-B27 antigen but no clinical or radiographic evidence of sacro-iliitis, is described. The patient did not fulfil the criteria for any of the seronegative spondylo-arthropathies. He was assessed as having the subtype of pauci-articular juvenile chronic arthritis, which occurs in older boys and is associated with HLA-B27, and he also had features of the seronegative enthesopathy and arthropathy syndrome, which has been reported in children. The HLA-B27-associated diseases, such as ankylosing spondylitis and Reiter's syndrome, are uncommon in black adults and there is very little data on their occurrence in black children. Suspicion of this entity in children will permit an accurate diagnosis and help to distinguish these children from those with other childhood rheumatic disorders.