Identification of a novel candidate locus for juvenile idiopathic arthritis at 14q13.2 in the Latvian population by association analysis with microsatellite markers.

To identify novel juvenile idiopathic arthritis (JIA) susceptibility loci, a 270 kb genomic region encompassing FAM177A1, KIAA0391, and PSMA6 genes was genotyped in 97 oligoarthritis (JIoA) and 50 polyarthritis (JIpA) patients and 230 individuals without autoimmune disorders by five microsatellites (MS) previously described as HSMS markers of the 14q13.2 region. Direct sequencing revealed two variable components of the (CAA)(n)(A)(m) motif in HSMS602 marker (FAM177A1 gene). Repeat (AC)(5)AT(AC)(n) of the HSMS701 (KIAA0391 gene) was variable in the Latvian population only in its downstream part. Allele (AC)(5)AT(AC)(15) of HSMS701 was found to be strongly associated with JIA (p = 4.91 x 10(-…