The primary purpose of this study is to detect patterns of immune abnormalities in the colitis associated with Hermansky-Pudlak Syndrome (HPS). Additionally we aim to document the clinical response to and tolerance of conventional inflammatory bowel disease (IBD) therapy for HPS patients with active colitis associated with Hermansky-Pudlak Syndrome (HPS). HPS is a rare autosomal recessive disorder causing dysfunctional lysosome-related organelle formation and trafficking resulting in oculocutaneous albinism and a bleeding diathesis secondary to platelet dysfunction. Associated conditions include pulmonary fibrosis, IBD, and systemic ceroid deposition. The associated IBD has been reported to occur at a higher frequency in the HPS-1 and HPS-4 subtypes compared to the prevalence of IBD in non-HPS populations. HPS IBD has clinical features of both ulcerative colitis (UC) and Crohn's disease, but histologically resembles Crohn's disease in that granulomas are commonly seen in the mucosa of the intestine. The pathogenesis of HPS IBD is not fully understood and little data beyond descriptions of the clinical and histologic manifestations have been published. Furthermore reports on treatment of the colitis in HPS patients are largely anecdotal, and our own experience suggests that many patients may be under-treated.