MUTATIONS IN THE CHEDIAK-HIGASHI-SYNDROME GENE (CHS1) INDICATE REQUIREMENT FOR THE COMPLETE 3801-AMINO-ACID CHS PROTEIN

Chediak-Higashi syndrome (CHS) is a rare, usually fatal, autosomal rec essive disorder characterized by severe immunologic defects, reduced p igmentation, progressive neurologic dysfunction and a bleeding diathes is, The hallmark of CHS is giant organelles and giant granules in many different cell types, most likely the result of defective trafficking of specific organellar and granular proteins necessary for the normal genesis, structure or function of these cytoplasmic components. The C HS1 gene has recently been identified and shown to be homologous to th e beige locus of the mouse; however, there has been disagreement as to the length of the functional CHS1 mRNA and protein, Here we report ho mozygous CHS1 gene mutations in two of the original probands we used t o map the gene to 1q42-q44, One of these, a frameshift at codon 3197, supports our assertion that the functional CHS protein is a predicted 3801 amino acid polypeptide encoded by a 13.5 kb mRNA.