How is Chédiak-Higashi syndrome (CHS) diagnosed?

Updated: Aug 08, 2019
  • Author: Roman J Nowicki, MD, PhD; Chief Editor: Dirk M Elston, MD  more...
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Answer

Diagnosis of Chédiak-Higashi syndrome (CHS) is made by recognition of the characteristic giant granules in neutrophils, eosinophils, and granulocytes by using light microscopy of a routine blood smear. Laboratory findings include neutropenia and hypergammaglobulinemia.

Bone marrow smears reveal giant inclusion bodies in leukocyte precursor cells. The granules are peroxidase positive and contain lysosomal enzymes, suggesting that they are giant lysosomes, or in the case of melanocytes, that they are giant melanosomes. The diagnostic hallmark is the occurrence of giant inclusion bodies in the peripheral leukocytes and their bone marrow precursors. [20]

In addition to the characteristic leukocytic dysfunctions, fluorescence cytometric analysis of cellular granularity and surface molecules offer useful diagnostic information.

Microscopic examination of the hair can also reveal clumped melanin granules, larger than those seen in normal hairs, and examination of the skin shows giant melanosomes both in keratinocytes and melanocytes, which can be us.

Definite diagnosis is based on the molecular genetic testing of CHS1. [14]

Molecular testing approaches can include the following:

  • Sequence analysis of LYST first followed by deletion/duplication analysis if only one or no mutation is found
  • Use of a multigene panel that includes LYST and other genes of interest used as a laboratory test for the differential diagnosis with other partial albinism disorders

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