Given that alternatively spliced isoforms of 5-LO have been identified in human leukocytes, a better understanding of the regulation of their expression and of the mechanisms by which they modulate LT biosynthesis will contribute to our understanding of the complex regulation of LT biosynthesis and may possibly lead to new approaches to the treatment of diseases like asthma and atherosclerosis in which 5-LO plays an active role. The gene discussed is ALOX5; the disease is asthma.