Background: The upper zone of growth plate and cartilage matrix-associated protein (UCMA), also called Gla-rich protein (GRP), is a novel protein found at sites af-fected by pathological calcifications.
Methods: We performed a full exon resequencing on DNA samples from 17 chronic kid-ney disease (CKD) patients (stage 5) and compared the results with 121 healthy con-trols in a Swedish population.
Results: A novel non-synonymous single nucleotide polymorphism (SNP) causing a car-boxy-terminal amino acid exchange was found. This SNP involves an alteration of the last ACC codon for threonine in exon 5 (adjacent to the stop codon) to an AGC ser-ine codon (138Thr > Ser). Six controls and two CKD patients were heterozygous for the 138Thr > Ser polymorphism. Both patients had histories of vascular calcifica-tion; however, it is uncertain whether this SNP has any significance for the func-tional domains of the UCMA protein. In addition, a heterozygous transversion muta-tion was found in a patient at SNP rs4750328 (A/G) in intron 2, involving an ex-change of the ancestral A allele to a T base.
Conclusions: The 138Thr > Ser polymorphism seems to be the only non-synonymous SNP found in the UCMA gene in a Swedish population.