Jul;43(7):514-20. September AV et al; Variants within the COL5A1 gene are associated with Achilles tendinopathy in two populations; Br J Sports Med; 2009 May;43(5):357-65. Glossary: Locus (plural loci): the specific location of a gene or DNA sequence on a chromosome, (e.g.; 8p21.1 is the p21.1 region on Chromosome 8). Gene :