DHDPSL is a 327 amino acid mitochondrial protein that catalyzes the last step in the hydroxyproline metabolic pathway. Existing as two alternatively spliced isoforms, DHDPSL is expressed in kidney and liver and is inhibited by divalent cations. Defects in the gene that encode DHDPSL are the cause of primary hyperoxalurea type III (HP3), a disorder of calcium oxalate nephrolithiasis. Patients with HP3 excrete urine with elevated levels of oxalate and L-glycerate. The DHDPSL gene maps to human chromosome 10, which contains over 800 genes and 135 million nucleotides. Defects in some of the genes that map to chromosome 10 are associated with Charcot-Marie Tooth disease, Jackson-Weiss syndrome, Usher syndrome, nonsyndromatic deafness, Wolman’s syndrome, Cowden syndrome, multiple endocrine neoplasia type 2 and porphyria