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Griscelli syndrome
Griscelli syndrome
Clinical features Griscelli syndrome is a rare disease inherited in an autosomal recessive fashion and characterized by skin hypopigmentation, silver-gray hair, neurological abnormalities, and recurrent infections secondary to immunodeficiency (Fig. 20.14).1โ3 Other features include hepatosplenomegaly, pancytopenia, hypoproteinemia, hypofibrinogenemia, and hypertriglyceridemia. Patients with neurological manifestations but no immunological
A skin biopsy from affected skin reveals that melanin is present in basal melanocytes but absent in keratinocytes. Examination of involved hair shafts reveals irregular clumps of melanin, particularly in the medulla of the hair shaft (Fig. 20.15). Cutaneous granulomas due to the immunodeficiency have been reported in Griscelli type 2.12
Differential diagnosis Distinction between Griscelli and Chรฉdiak-Higashi syndromes is possible with the use of polarized light to examine hair shafts. In both conditions, larger than normal melanin granules are seen.13 However, in the latter disease, the granules are evenly distributed with bright and polychromatic appearance under polarized light. In Griscelli syndrome, granules are larger and more irregular, tend to aggregate near the medulla, and have a white appearance under polarized light.
998 Disorders of pigmentation
Fig. 20.14 Griscelli syndrome: cutaneous hypopigmentation and silvery hair. By courtesy of M. Canningavan, MD, University of Utrecht, the Netherlands.
Fig. 20.15 Griscelli syndrome: clumps of melanin within hair shafts. By courtesy of M. Canningavan, MD, University of Utrecht, the Netherlands.