Griscelli syndrome.

Griscelli syndrome is a congenital autosomal recessive syndrome of combined immunodeficiency and partial albinism, first described in France by Claude Griscelli. Albinism in this syndrome is caused by a defect in the migration of melanosomes from melanocytes (where pigment is formed) to keratocytes. Two genes have been identified whose defect leads to the formation of the Griscelli phenotype: the Myosin 5a gene and the Rab 27a gene. The products of these genes are proteins involved in the transport of melanosomes and secretory granules of cytotoxic lymphocytes to the cell surface.

Griselli syndrome differs from Chediak-Higashi syndrome by the absence of giant granules in leukocytes. Before the discovery of a specific genetic defect, the characteristic distribution of melanin in the hair follicles, being pathognomonic, served as the basis for diagnosing the syndrome. Patients are predisposed to fungal, viral and bacterial infections. Immunodeficiency can manifest itself as a decrease in the level of immunoglobulins, as well as a violation of cellular immunity, in particular, a violation of T-cell cytotoxicity and a decrease in the function of NK cells. Most patients develop a phase of lymphohistiocytic acceleration, similar to that in Chediak-Higashi syndrome, and requiring remission induction. The only radical method of treating children with Griselli syndrome is HSCT.