The existence of a DNA polymorphism at the hormone-sensitive lipase locus could be of great interest for genetic analysis of obesity and related disorders since hormone-sensitive lipase is the rate-limiting enzyme of adipose tissue lipolysis and therefore plays a key role in energy metabolism. The polymorphic dinucleotide repeat D19S120 was identified within a human genomic clone selected with a rat hormone-sensitive lipase cDNA. This marker was subsequently localized to the short arm of chromosome 19 (p13.3) whereas human hormone-sensitive lipase (LIPE) had been mapped to the long arm of chromosome 19 (q13.1-->13.2). A duplication of the hormone-sensitive lipase gene or the presence of a pseudogene could explain the discrepancy. Cosmids from the two regions were analyzed in Southern blot experiments. A human adipose tissue hormone-sensitive lipase full-length cDNA probe hybridized only to cosmids from the 19q13.1-->13.2 region whereas the D19S120 amplicon probe hybridized only to cosmids from the p13.3 region. These data show that the occurrence of gene duplication or the presence of a pseudogene on the short arm of chromosome 19 is very unlikely and that D19S120 is unrelated to the hormone-sensitive lipase gene.