Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by pigment dilution, nystagmus, decreased visual acuity, a bleeding diathesis, and lysosomal accumulation of ceroid lipofuscin. Electron microscopic evidence demonstrating lack of platelet-dense bodies provides the sine qua non for diagnosing HPS. Ceroid lipofuscinosis is considered to cause several serious complications, including progressive pulmonary fibrosis leading to death in the fourth or fifth decades. Currently, only symptomatic treatment can be offered. Although rare in the general population, HPS occurs in northwest Puerto Rico with a prevalence of 1 in 1800. HPS1, the first gene found to be responsible for HPS, was mapped to chromosome 10q23 and subsequently isolated and sequenced. It consists of 20 exons encoding a 700-amino acid, 79.3-kDa peptide with no homology to any known protein. All 10 HPS1 mutations reported to date, including the 16-bp duplication found in all northwest Puerto Rican patients, result in truncated proteins. The two mutations in the mouse pale ear gene (ep), which is the murine homology of HPS1, cause similarly truncated proteins. The pathologic nature of these truncation mutations may result from unstable mRNA. However, in combination with the absence of any disease-causing missense mutations, it may indicate that the C-terminus of the HPS1 peptide is functionally important. The disorder HPS displays locus heterogeneity, consistent with the existence of 14 mouse strains manifesting both hypopigmentation and a platelet storage pool deficiency. Two mouse models, pearl and mocha, have mutations in the beta3A and delta subunits of the adaptor-3 complex, respectively. This suggests that defective vesicular trafficking, specifically cargo packaging, vesicle formation, vesicle docking, or membrane fusion, may comprise the basic defect in HPS. Studies of the proteins involved in intercompartmental transport for melanosomes, platelet-dense bodies, and lysosomes should lead to a better understanding of the mechanisms of organellogenesis and to more effective therapies for HPS.
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PMID:Hermansky-Pudlak syndrome: models for intracellular vesicle formation. 978

Hermansky-Pudlak syndrome (HPS) develops from defects in the biogenesis and/or function of lysosome-related organelles essential to membrane and protein trafficking. Of the eight known human subtypes, only HPS-1 and HPS-4 develop pulmonary fibrosis in addition to the general clinical manifestations of oculocutaneous albinism and bleeding diathesis. We identified HPS-1 in three unrelated patients from different regions of India, who presented with iris transillumination, pale fundi, hypopigmentation, nystagmus, decreased visual acuity, and a bleeding diathesis. Two of these patients carried the homozygous mutation c.398+5G>A (IVS5+5G>A) in HPS1, resulting in skipping of exon 5 in HPS1 mRNA. The third patient carried a novel homozygous c.988-1G>T mutation that resulted in in-frame skipping of HPS1 exon 12 and removes 56 amino acids from the HPS1 protein. Given the discovery of HPS-1 in an ethnic group where oculocutaneous albinism (OCA) is highly prevalent, it is possible that HPS in India is under-diagnosed. We recommend that unconfirmed OCA patients in this ethic group be considered for mutational screening of known HPS genes, in particular c.398+5G>A and c.980-1G>T, to ensure that patients can be monitored and treated for clinical complications unique to HPS.
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PMID:Hermansky-Pudlak syndrome type 1 in patients of Indian descent. 1939 12

Oculocutaneous albinism (OCA), which is roughly divided into non-syndromic and syndromic OCA, is a group of autosomal recessive disorders caused by mutations in genes associated with pigmentation. Patients with OCA have hypopigmentation and ocular manifestations such as photophobia, amblyopia, and nystagmus. Hermansky-Pudlak syndrome (HPS), the most common syndromic OCA, is characterized by the additional features of a bleeding tendency and other critical systemic comorbidities such as pulmonary fibrosis and immunodeficiency. NGS-based gene analyses have identified several new causative genes for OCA and have detected rare subtypes of OCA with high accuracy including Japanese patients. In our survey of 190 Japanese OCA patients/families, OCA4 is the most common subtype (25.3%) followed by OCA1 (20.0%), HPS1 (14.7%), and OCA2 (8.4%). Similar to the A481T variant in OCA2, which is associated with a mild form of OCA2 and skin color variation, the c.-492_489delAATG variant located in the promoter region of SLC45A2 has been uniquely identified in Japanese patients with a mild form of OCA4. Further, rare OCA subtypes, including OCA3, HPS2, HPS3, HPS4, HPS5, HPS6, and HPS9, have also been identified in Japanese patients. The clinical characteristics and underlying molecular mechanisms of each subtype of OCA are concisely summarized in this review.
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PMID:Current landscape of Oculocutaneous Albinism in Japan. 3296 95