albinism

..Our results suggest that sequences in the immediate vicinity of the mouse tyrosinase gene are sufficient to provide cell type-specificity and developmental regulation in melanocytes and the pigment epithelium...

..These results point to spatiotemporal defects in neuronal production in the albino retina, which could perturb expression of genes that specify cell fate, number, and/or projection phenotype...

..are associated with tyrosinase (TYR) gene mutations; therefore TYR was considered the candidate gene for albinism in mink. Four microsatellite markers were chosen in the predicted region of the TYR gene...

..a tyrosinase gene mutation in several patients with classic, tyrosinase-negative (type IA) oculocutaneous albinism. This mutation, which results in a proline----leucine substitution at codon 81 of the tyrosinase polypeptide (EC ..

..exons of the tyrosinase gene of three British patients suffering from tyrosinase negative oculocutaneous albinism has revealed three new missense point mutations: (1) an adenine to guanine transition at codon 1 changes the ..

b>Albinism, caused by a deficiency of melanin pigment in the skin, hair, and eye (oculocutaneous albinism [OCA]), or primarily in the eye (ocular albinism [OA]), results from mutations in genes involved in the biosynthesis of melanin ..

A mother and her son with albinism and sensorineural deafness compatible with Tietz syndrome (MIM 103500) are reported...

..Here we report an increased frequency of partial albinism, a morphological aberration associated with a loss of fitness, among barn swallows, Hirundo rustica, breeding ..

..Because the same mutations were identified in different breeds with similar phenotypes, the mutations are likely to be identical by descent rather than multiple mutation events occurring at the same site...

..Although the tyrosinase mRNA levels are similar in c2j and wildtype, the protein is virtually absent in c2j, as in c, possibly due to proteolytic degradation...

Oculocutaneous albinism (OCA) is an autosomal-recessive genetic disorder defined by hypomelanosis in the eyes, hair, and skin. Piebaldism is an autosomal-dominant congenital leukoderma associated with a white forelock...

..We focused on the trait of albinism and discovered that it is linked to Oca2, a known pigmentation gene, in two cave populations...

..Most of these functions are not yet understood. Deficit of melanin pigment is associated with age-related macula degeneration, the leading cause of blindness...

..Melanosomes also use a lysosome-related organelle to secrete melanin for pigmentation. Links between albinism and immunity in patients have uncovered a number of key proteins required for lysosomal secretion and have ..

..b>Albinism, a genetic condition of reduced melanin synthesis, is a major public health issue in southern Africa...

The genetic condition albinism has a high frequency among the Sotho people of northern South Africa. Affected children have pale hair, eyes and skin-a dramatic contrast to the normal dark pigmentation...

b>Albinism is a relatively common genetic condition in Zimbabwe, a tropical country in southern Africa. Those affected have little pigment in their hair, skin or eyes, in sharp contrast to the normal dark pigmentation...

Murine albinism is characterized by complete lack of melanin pigments in skin and retina. In order to study the molecular basis of albinism, we have cloned and characterized the tyrosinase gene of BALB/c mice (c/c)...

Basal cell carcinoma (BCC) is the most common cutaneous malignancy in the white population and occurs infrequently in dark-pigmented individuals. Albinism is an established risk factor for skin cancer in black Africans.

..Barn swallows from Chernobyl had a temporally constant, elevated frequency of partial albinism compared to the situation before radioactive contamination and compared to birds from a control area...

..Diagnostic genotyping tests were developed to detect this mutation in Braunvieh cattle...

Patients and vertebrate mutants with oculocutaneous albinism type 4 (OCA4) have mutations in the solute carrier family 45 member 2 (slc45a2) gene. However, there is no empirical evidence for this gene-phenotype relationship...

b>Albinism was one of the first genetic diseases to be noted in humans, but until relatively recently, little was known of the molecular mechanisms involved in its pathogenesis...

There are several syndromes of albinism associated with systemic pathology...

..We compare eye and skin pigmentation phenotypes and the genetic lesions that cause each. We suggest that this panel of congenic mutants contains rich, untapped resources for the study of many questions of basic cell biological interest...

Type II (tyrosinase-positive) oculocutaneous albinism is an autosomal recessive disorder that has recently been mapped to chromosome segment 15q11-q13...

..No cases of cutaneous melanoma or Kaposi sarcoma were found in the albino group...

Tyrosinase-negative oculocutaneous albinism (OCA) is an inborn error of metabolism, characterized by a complete lack of melanin pigments in the eyes and skin. We have isolated and characterized the tyrosinase gene of one affected child (S...

b>Albinism is a genetic condition associated with abnormalities of the visual system...

X-linked albinism-deafness syndrome (ADFN) was described in one Israeli Jewish family and is characterized by congenital nerve deafness and piebaldness...

..To investigate the different components of full-field flash electroretinogram (ERG) responses in adult albino and pigmented rats at various time intervals following optic nerve transection (ONT)...

..14.18.1), the key enzyme in melanin synthesis. Similar to type IB oculocutaneous albinism in humans, overall production of pigment is greatly reduced in dark-eyed albino mice and obvious only in the eyes...

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..It is unlikely that levofloxacin causes toxicity because of its much lower affinity to melanin-containing ocular tissues and shorter duration of therapy compared to chloroquine...

..Mouse tyrosinase mRNA is approximately 2.4 Kb in size. The amount of tyrosinase mRNA reflects the levels of tyrosinase activity in normal melanocytes and Cloudman S-91 melanoma cell line...

..synthesis in skin and eye and of cyclic guanosine monophosphate phosphodiesterase gene defects, which results in albinism (Tyr(c/c)) and retinal degeneration (Pde6b(rd1/rd1)), respectively...

..We used a congenic strain of albino and pigmented rats with a mutation at the c locus for albinism (Fischer 344-c/+; LaVail MM, Lawson NR (1986) Development of a congenic strain of pigmented and albino rats for ..

Type I oculocutaneous albinism (OCA) is an autosomal recessive disorder caused by the reduction or the absence of tyrosinase (TYR) activity in melanocytes of the skin, hair and eyes. Here we report an analysis of 45 patients with OCA...

There has been long-standing clinical and electrophysiological evidence that in patients with albinism the visual pathways cross atypically: most fibres from one eye cross to the contralateral visual cortex...

b>Albinism, due to a lack of melanin pigment, is one of the oldest known mutations in mice. Tyrosinase (monophenol oxygenase, EC 1.14.18...

..14.18.1), and defective tyrosinase leads to albinism. The mechanisms for other pigmentation determinants (e.g...

..Localized gene correction was maintained three months after the last application of the chimeric oligonucleotides. These results demonstrated correction of the tyrosinase gene point mutation by chimeric oligonucleotides in vivo...

..These results indicate the possibility that the altered residue at amino acid 420 of mouse tyrosinase may be important in stabilization of the tyrosinase molecule, or in interaction with other molecules, such as tyrosinase inhibitors...

..We suggest that mouse models of the organization and development of the optic chiasm are not common to placental mammals in general...

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..Oculocutaneous albinism type I, a common form of albinism, is caused by mutations in the tyrosinase gene...

..Tyrosinase, the primary enzyme in melanin synthesis commonly mutated in albinism, oxidizes l-tyrosine to l-dopaquinone using l-3,4-dihydroxyphenylalanine (L-DOPA) as an intermediate product...

..The establishment of the transgenic model provides a unique tool with which to investigate the way in which melanin shapes this region of the developing mammalian visual system...

..In humans mutations in the TYR gene are associated with type 1 oculocutaneous albinism (OCA1) that leads to reduced or absent pigmentation of skin, hair and eye...

..The pattern of pigmentation in mosaic revertants indicates frequencies of melanin pigments to be consistent with the numbers of melanophores per unit area of body sites, such as the eyes, head and dorsal trunk...

..This model also allows the rapid and systematic examination of parameters for the effective use of synthetic peptide vaccines...

..Southern blot analysis of DNA derived from newborn mice carrying lethal albino deletion mutations revealed that Pmel34 maps near or at the c-albino locus, the position of the structural gene for tyrosinase...

In albinism a large proportion of nerve fibres originating in temporal retina cross the midline at the chiasm and project to the contralateral hemisphere...

..b>Albinism often leads to deafness in animals, indicating a genetic correlation...

..to produce pigment, or transport or transfer melanosomes is associated with several diseases such as vitiligo, albinism and Hermansky-Pudlak syndrome...

..The results of these experiments are consistent with the hypothesis that ocular hypopigmentation causes elevated calcium levels in the subretinal space that in turn mimic light adaptation in hypopigmented mice...

..To explore the relationship between melanin synthesis and the congenital high myopia of albino guinea-pigs...

..The i(b) allele at this locus, also denoted as i( 5), causes oculocutaneous albinism in homozygous carriers...

..SELH/Bc mice may provide an animal model for the study of mechanisms underlying genetic instability...

..was used to establish linkage of a quantitative trait locus influencing ethanol-induced anesthesia to the albinism gene (Tyr) in mouse...

..in other species are associated with tyrosinase (TYR) mutations, TYR was proposed as a candidate gene for albinism in cats...

..These observations have important implications for the design and interpretation of positional cloning experiments...

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In albinism there is an abnormal projection of part of the temporal retina to the visual cortex contralateral to the eye...

..domestication has negatively affected the visual function of laboratory rat strains, what the effects of strain albinism are on rat visual function, or whether there are strain differences in the visual function of laboratory rats ..

..These data suggest that the age-related changes in the serotonergic system in the superior colliculus and pretectum may account for some of the alterations in light-mediated behaviors with aging...

..The mutations uncovered by our behavioral assays provide distinct entry points for the study of visual pathways and set the stage for a genetic dissection of vertebrate vision...

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..This is consistent with abnormal decussation at the optic chiasm in albinism. Finally, we report a case where a lesion to white matter has resulted in a lack of measurable activity in ..

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..Overall, we were unable to confirm a previous report that a 50-fold difference in rod sensitivity existed between neonatal and adult rats...

..Thus, pigmented melanocytes apparently contain antioxidants more potent than glutathione, protecting them from ultraviolet-A-induced membrane damage...

Reduction of the melanin precursor DOPA associated with albinism leads to spatiotemporal disturbances in retinal neurogenesis and thus seems to be responsible for numerous neuronal alterations found in albino retinae...

..Thus, the defect rendering albino ferrets optokinetically nonresponsive is located in the visual pathway subserving the OKR, namely in or before the NOT-DTN, and not in oculomotor centers...

..in the Rab27a gene cause pigment as well as cytotoxic granule transport defects, accounting for the partial albinism and severe immune disorder characteristics of this syndrome...

b>Albinism is associated with a misrouting of fibers at the optic chiasm where the majority of fibers cross to the contralateral side...

In humans with albinism, a large percentage of the ganglion cell axons from the temporal retina decussate abnormally in the chiasm and synapse in the contralateral LGN...

..These changes have implications for our understanding of development and plasticity of the central visual pathways...

A characteristic feature of patients with albinism is the misrouting of the optic nerves, which causes the visual cortex to receive an abnormal input...

Oculocutaneous albinism (OCA) is a group of inherited disorders of melanin biosynthesis characterized by a generalized reduction in pigmentation of hair, skin and eyes...

..manifestations such as ichthyosis, chondrodysplasia punctata, hypogonadotropic hypogonadism, anosmia, ocular albinism, short stature and mental retardation...

Ocular albinism of the Nettleship-Falls type (OA1) and X-linked ichthyosis (XI) due to steroid sulfatase (STS) deficiency are cosegregating in three cytogenetically normal half-brothers...

..The complete syndrome includes oculocutaneous albinism with photophobia, neurologic features, recurrent infections, and enterocolitis.

To elucidate the molecular genetic defect of X linked congenital nystagmus associated with macular hypoplasia in three white males of a three generation family with clear features of ocular albinism in only one of them.

..of enzymes functional in melanogenesis such as tyrosinase, P protein and DHICA oxidase, result in oculocutaneous albinism (OCA) 1, OCA 2, and OCA 3, respectively...

Hermansky-Pudlak syndrome (HPS), consisting of oculocutaneous albinism and a bleeding diathesis due to the absence of platelet dense granules, displays extensive locus heterogeneity...

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder characterized by oculocutaneous albinism and a storage pool deficiency due to an absence of platelet dense bodies...

..3 region to be responsible for genetically heterogeneous diseases. In this study, fluorescence in situ hybridization (FISH) methods were used to detect the extent of gene deletion related to the phenotypes of patients with Xp-CGS...

Autosomal recessive ocular albinism (AROA) is a group of genetic disorders in which reduced pigmentation of the eye is associated with decreased visual acuity, nystagmus, strabismus, and photophobia, although pigmentation of skin and hair ..

..In this group, defined as children with subnormal visual acuity syndromes (SVAS), albinism was shown to be a major cause to the visual dysfunction giving a prevalence of about 1%...

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Hermansky-Pudlak Syndrome (HPS) is a type of oculocutaneous albinism associated with a bleeding diathesis and pulmonary fibrosis...

The dual purpose of this study was to determine the genotype of patients with oculocutaneous albinism type 1 and 2 based on analysis of tyrosinase and P gene mutations and to attempt to establish a correlation between phenotype and ..

..Homozygosity for a mutation in the P locus mapped to the human chromosome 15q11.2-12 results in tyrosinase-positive albinism (OCA2)...

Ocular albinism type 1 (OA1) is an X-linked recessive disorder characterized by a major impairment of visual acuity, nystagmus, strabismus, photophobia and retinal hypopigmentation...

To evaluate the spectrum of foveal architecture in pediatric albinism and to assess the utility of spectral-domain optical coherence tomography (OCT) in ocular imaging of children with nystagmus.

..The human orthologue is the P protein. Humans lacking a functional P protein have oculocutaneous albinism type 2 (OCA2)...

..syndrome (HPS) is an autosomal recessive inherited disease consisting of (1) partial oculocutaneous albinism (with nystagmus, strabism, and visual acuity loss), (2) platelet storage pool deficiency (with bleeding diathesis)..

b>Albinism is a heterogeneous group of genetic disorders characterized by reduced or absent melanin pigmentation, mainly involving the eyes, skin, and hair...

..Defects in melanosome formation cause oculocutaneous albinism (OCA), a condition associated with impaired vision and enhanced cancer susceptibility in the skin and eye...

..While much is known about the neural phenotype associated with ocular albinism (OA) and related hypopigmentation conditions affecting the retinal pigment epithelium (RPE), how these changes ..

Signal Transduction Mechanisms in Ocular Albinism Patients with X-linked ocular albinism type 1 display decreased pigmentation of ocular tissues and suffer a characteristic series of traits that includes poor visual acuity, nystagmus, ..

..pigmentation defects and visual problems associated with several human genetic disorders, such as X-linked ocular albinism 1 (OA1) and various types of Hermansky-Pudlak syndrome (HPS)...

..mechanisms that regulate melanin synthesis and characterize the pathogenesis of pigment-related disorders such as albinism. We will focus our efforts on the OCA2 gene, which is mutated in oculocutaneous albinism type 2, the most common ..

..mechanisms that regulate melanin synthesis and characterize the pathogenesis of pigment-related disorders such as albinism. We will focus our efforts on the OCA2 gene, which is mutated in oculocutaneous albinism type 2, the most common ..

..Syndrome (HPS) is a congenital, potentially fatal, multi-system disorder presenting with oculocutaneous albinism, a mild to severe bleeding diathesis, and ceroid storage disease...

..Among the symptoms of HPS is oculocutaneous albinism due to malformation of melanosomes, lysosome-related organelles in eye pigment epithelia and melanocytes of the ..

..Mutations in tyrosinase are the cause of tyrosinase-negative albinism. Many of these mutated forms contain amino acid substitution that have the potential to reduce the efficiency of ..

..Investigations of the visual system in subjects with albinism and known genotypes are also planned in collaboration with Genetics...

..with the similar coupled binuclear copper sites in hemocyanin, Ty, mutants of Ty associated with oculocutaneous albinism, and catechol oxidase related to differences in function; 2) Definition of the coordinatively unsaturated nature ..

DESCRIPTION: (Applicant's Abstract) Individuals with ocular albinism (OA) lack stereoscopic vision due to a reduction of the ipsilateral component of the optic tract and have deficient melanin levels in the retinal pigment epithelium (..

..chiasm also patterns binocular vision, and if RGC divergence is mis-apportioned in inherited defects such as albinism, reduced visual acuity and strabismus ensue...

..HPS), defects in the lysosome-related organelles (melanosomes, platelet dense bodies, and lysosomes) result in albinism, prolonged bleeding, and lysosomal ceroid pigment deposition...

..sort tyrosinase or gp100 to the melanosome results in developmental and pigment defects such as oculocutaneous albinism. Melanosomal sorting may also affect immune responses to melanoma; tyrosinase and gp100 are among the few human ..