Pelger-Huët is a relatively rare, autosomal dominant disorder in which neutrophilic and eosinophilic granulocytes have only two-lobed nuclei due to a mutation in the lamin-B receptor gene. The granulocytes of homozygous affected patients may have impaired function as a result.

Much more often, however, this abnormality is seen in hematologic stress due to infection, trauma or malignancy. One then speaks of pseudo Pelger-Huët. The two forms are easily distinguished from each other because in pseudo Pelger-Huët, normal granulocytes can always be found.