Dorfman-Chanarin syndrome is a rare autosomal recessive inherited
lipid storage disease characterized by
ichthyosis, leukocyte
lipid vacuoles, and involvement of several internal organs. Recently, CGI-58 mutations were identified as the cause of
Dorfman-Chanarin syndrome. The physiologic roles of the CGI-58
protein and the pathomechanisms of
Dorfman-Chanarin syndrome still remain to be clarified, however. The patient, a 16-y-old male, demonstrated
ichthyosis, small ears,
lipid vacuoles in his leukocytes,
liver dysfunction, and
mental retardation. Sequencing of CGI-58 revealed that the patient was homozygous for a novel
nonsense mutation R184X, in exon 4. The putative truncated
protein was 52.4% of the length of the normal CGI-58
polypeptide and lacked approximately 60% of the
lipid binding region, 66.4% of the alpha/beta
hydrolase folding segment of the
polypeptide, and two of the CGI-58 catalytic triads, resulting in a significant loss of
lipase/
esterase/thioesterase activity. Electron microscopy revealed a large number of abnormal lamellar granules, a disturbed intercellular lamellar structure, and
lipid vacuoles in the epidermis. These results suggested that CGI-58
protein is involved in the lipid metabolism of lamellar granules and that defective
lipid production in lamellar granules caused by a CGI-58
protein deficiency is involved in the pathogenesis of
ichthyosis in
Dorfman-Chanarin syndrome.