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  Pigmentary Dilution




The transport of vesicles from the golgi network are required for proper development and functioning of neutrophils, melanocytes, and platelets. In addition, transport of granules to the immunologic synapse is required for intact CD8 T cell and NK cell cytotoxicity. The following disorders all result from impaired vesicular transport and regulation



Chediak-Higashi Syndrome


Chediak-Higashi syndrome - Patients are characterized by partial oculocutaneous albinism, bleeding disorder from platelet dysfunction, chronic neutropenia, and defective cell cytotoxicity. Skin, iris, and hair show evidence of hypopigmentation. This disease is caused by mutations in LYST, a protein involved in granule transport.




Griscelli Syndrome Type II


Griscelli syndrome type II - GS type II is caused by mutations in the gene RAB27A. This protein is required for proper granule transport along microtubule tracks. Patients have prominent hypopigmentation with silvery gray hair that is more pronounced than patients with Chediak-Higashi. Patients have impaired CD8 T cell and NK cell cytotoxicity.



Hermansky-Pudlak Syndrome

Hermansky-Pudlak syndrome II - HPS type II is characterized by oculocutaneous albinism, bleeding disorder due to platelet dysfunction, and chronic neutropenia. This disease results from mutations in the gene AP3B1 which encodes for the -subunit of AP-3, which interacts with the protein clathrin to mediate protein sorting in the golgi network and endosome.



P14 Deficiency

P14 deficiency - Patients have hypopigmentation, short stature, and immunodeficiency (neutropenia and decreased cell cytotoxicity). P14 is believed to play a role in regulation of the late endosomal compartment. Dyskeratosis congenital - Patients may develop diffuse hypo- or hyperpigmentation. Lacy reticular pigmentation of the upper chest and neck also occurs. Other cutaneous findings include nail dystrophy and oral leukoplakia.


Nijmegen Breakage Syndrome

Nijmegen breakage syndrome - Patients can develop café au lait spots as well as vitiligo. Patients also have microcephaly, bird-like facies, and predisposition to cancer.  The combined immunodeficiency is characterized by hypogammaglobulinemia and low T cell numbers/function.


Bloom Syndrome

Bloom syndrome - Patients can develop patchy areas of hypopigmentation or hyperpigmentation, especially on the trunk. Patients can also develop telangiectatic erythema on sun exposed areas of the face (similar to the butterfly rash seen in SLE) which can be bright red and disfiguring in extreme cases.

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