AlderâÂÂReilly anomaly, or Alder anomaly, is an inherited abnormality of white blood cells associated with mucopolysaccharidosis. When blood smears and bone marrow preparations from patients with AlderâÂÂReilly anomaly are stained and examined microscopically, large, coarse granules may be seen in their neutrophils, monocytes, and lymphocytes. The condition may be mistaken for toxic granulation, a type of abnormal granulation in neutrophils that occurs transiently in inflammatory conditions.
In addition to mucopolysaccharidosis, AlderâÂÂReilly anomaly may occur in lipofuscinosis and TayâÂÂSachs disease. While the anomaly is generally considered to exhibit autosomal recessive inheritance, it may also occur in carriers who are heterozygous for the TayâÂÂSachs mutation, although the inclusions are much less frequent than in homozygotes. AlderâÂÂReilly anomaly is not diagnostic of any disorder and does not correlate with disease severity. Affected white blood cells function normally.
AlderâÂÂReilly inclusions stain appear violet when treated with WrightâÂÂGiemsa stain and, in mucopolysaccharidosis, stain metachromatically with toluidine blue. Metachromatic staining is not seen in TayâÂÂSachs disease. The granules tend to be round or comma-shaped and may be surrounded by a clearing in the cytoplasm.