Parkinson's disease (PD) is a common neurodegenerative disorder with clinical features of bradykinesia, rigidity and resting tremor resulting from the deficiency of dopamine in the nigrostriatal system. Previously we mapped a susceptibility gene for an autosomal dominant form of PD to a 10.6 cM region of chromosome 2p (PARK3; OMIM 602404). Here we report the identification and characterization of the human sideroflexin 5 gene (SFXN5), which maps to the critical PARK3 region. Database analysis and 5'-RACE (rapid amplification of cDNA ends) identified a 4191 bp cDNA, encoding a predicted protein of 340 amino acids. The genomic sequence and structure of SFXN5 confirmed the cDNA sequence. Northern blot analysis revealed a single SFXN5 transcript of approximately 4.3 kb, which was primarily expressed in the brain. An examination of SFXN5 expression in specific regions of the human brain revealed high levels of expression in all regions analyzed. Sequence analysis of 2p13 linked individuals affected with PD did not reveal any potentially pathogenic mutations within SFXN5, suggesting SFXN5 does not correspond to PARK3.