Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder in which 
an immune deficiency occurs in association with pigmentation abnormalities. Most 
patients who do not undergo bone marrow transplantation die of a 
lymphoproliferative syndrome, though some patients with CHS have a relatively 
milder clinical course of the disease. The large size of the LYST gene, 
defective in CHS, has made it difficult to screen for mutations in a large 
number of patients. Only 8 mutations have been identified so far, and all lead 
to a truncated LYST protein. We conducted protein truncation tests on this gene 
in 8 patients with CHS. Different LYST mutations were identified in all subjects 
through this approach, strengthening the observation of a high frequency of 
truncated LYST proteins as the genetic cause of CHS.