Do alleles at the serum amyloid A locus influence susceptibility to reactive amyloidosis in systemic onset juvenile chronic arthritis?

Restriction fragment length polymorphisms of the serum amyloid A, gene have been used to distinguish three alleles:-a1, a2 and β. The relative frequencies of these alleles in patients with systemic onset juvenile chronic arthritis (S-JCA) match those in healthy control individuals. Subdivision of the S-JCA patient group, into those with and without reactive amyloidosis, reveals a highly significant co-segregation of the SAA2a2 allele with the amyloidotic condition.