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At least 19 recordsLinked to original sources
PubMed1979

Albinism.

There are seven forms of oculo-cutaneous albinism, which are all autosomal recessive: three are tyrosinase-negative (complete oculo-cutaneous albinism, Amish albinism, Hermansky-Pudlak syndrome) and four are tyrosinase-positive (incomplete oculo-cutaneous albinism, Chediak-Higashi syndrome, Cross syndrome, Bergsma's albinism). There are three forms of sex-linked albinism: ocular albinism, which is intermediary sex-linked, François-De Rouck syndrome and Ziprkowski syndrome, which show a generalized albinism and are recessive sex-linked. There are two principal forms of cutaneous albinism, one without deafness and the other with deafness (Waardenburg-Klein syndrome).

Albinism↗
PubMed1979

Partial oculocutaneous albinism in Mystromys albicaudatus: nonhomology with the Chediak-Higashi syndrome.

Partially albinic Mystromys albicaudatus were examined to determine if the condition in these animals was homologous with the Chediak-Higashi syndrome. Tissues and cells from partially albinic and normal Mystromys albicaudatus were studied by light and electron microscopy. No evidence of cytoplasmic granule enlargement, which is characteristic of the Chediak-Higashi syndrome, was detected in the cells of the partially albinic rats when compared to controls. It was concluded that the inherited condition of partial albinism of Mystromys albicaudatus was not homologous with the inherited partially albinic disease known as the Chediak-Higashi syndrome.

Albinism↗
PubMed2025

Multi-Omics Analysis of the Potential Mechanisms of Skin Albinism in Edangered Percocypris pingi: Abnormal Ubiquitination and Calcium Signal Inhibition.

Percocypris pingi is an endangered protected fish species in China. Its albino variants exhibit growth retardation and physiological abnormalities. Understanding its albinism mechanism holds significant scientific importance for molecular breeding programs and disease model development. This study integrated transcriptomic and proteomic analyses, combined with histopathological and molecular biological techniques, to systematically compare molecular differences in skin tissues between albino and wild-type P. pingi, with a focus on elucidating the multidimensional regulatory mechanisms underlying skin albinism. Our findings suggest that albinism in P. pingi is synergistically driven by hyperactivation of ubiquitin-mediated proteolysis (which suppressed TYR/TYRP1 enzymatic activity and disrupted the pH homeostasis of melanosomes), and inhibition of calcium signaling (which impeded melanin transport). This discovery provides novel insights into the mechanisms of pigment loss in fish species and offers a valuable reference for molecular breeding of endangered species as well as research on pigmentation-related disorders.

Animals↗
PubMed2017

OCA2 splice site variant in German Spitz dogs with oculocutaneous albinism.

We investigated a German Spitz family where the mating of a black male to a white female had yielded three puppies with an unexpected light brown coat color, lightly pigmented lips and noses, and blue eyes. Combined linkage and homozygosity analysis based on a fully penetrant monogenic autosomal recessive mode of inheritance identified a critical interval of 15 Mb on chromosome 3. We obtained whole genome sequence data from one affected dog, three wolves, and 188 control dogs. Filtering for private variants revealed a single variant with predicted high impact in the critical interval in LOC100855460 (XM_005618224.1:c.377+2T>G LT844587.1:c.-45+2T>G). The variant perfectly co-segregated with the phenotype in the family. We genotyped 181 control dogs with normal pigmentation from diverse breeds including 22 unrelated German Spitz dogs, which were all homozygous wildtype. Comparative sequence analyses revealed that LOC100855460 actually represents the 5'-end of the canine OCA2 gene. The CanFam 3.1 reference genome assembly is incorrect and separates the first two exons from the remaining exons of the OCA2 gene. We amplified a canine OCA2 cDNA fragment by RT-PCR and determined the correct full-length mRNA sequence (LT844587.1). Variants in the OCA2 gene cause oculocutaneous albinism type 2 (OCA2) in humans, pink-eyed dilution in mice, and similar phenotypes in corn snakes, medaka and Mexican cave tetra fish. We therefore conclude that the observed oculocutaneous albinism in German Spitz is most likely caused by the identified variant in the 5'-splice site of the first intron of the canine OCA2 gene.

Albinism, Oculocutaneous↗
PubMed1977

Trysinase positive oculocutaneous albinism in the goldfish, Carassius auratus l., and ultrastructural and biochemical study of the eye.

Ultrastructural studies, and cytochemical and biochemical determinations of tyrosinase activity were conducted on the pigment epithelium of albino and xanthic goldfish eyes. In eyes of xanthic goldfish, two types of melanosomes are present, spherical and elongated. Melanized melanosomes are absent in the eyes of the albino goldfish, but elongated lamellar premelanosomes are observed. Internal vesicles are present in both melanosome types in the pigment epithelium of the xanthic goldfish but are absent in premelanosomes of the albino. There are also differences in the distribution of lipid droplets, smooth endoplasmic reticulum and Golgi complexes with the latter two being more abundant in the albino. Tyrosinase was not identified cytochemically; however, the enzyme was demonstrated biochemically in the pigment epithelia of both albino and xanthic goldfish. The enzyme is associated with the particulate and soluble fractions fo both types of eyes. Particulate albino tyrosinase may be solubilized by triton X-100 treatment. Tyrosinase inhibitors are present in the particulate fractions of both albino and xanthic goldfish eyes. Thus, in the goldfish, ocular albinism appears to be a multiple defect at the molecular and ultrastructural levels.

Albinism↗
PubMed1979

Embryonic appearance of alpha, beta, and gamma crystallins in the periodic albinism (ap) mutant of Xenopus laevis.

The appearance of the crystallins during lens development in the periodic albinism (ap/ap) mutant of Xenopus laevis has been studied. Using antibodies specific for total crystallins, alpha + beta crystallins, and gamma crystallins in the immunofluorescence technique, the first positive reaction for all could be demonstrated in the Nieuwkoop-Faber Stage 31 lens rudiment. The antibody to alpha + beta crystallins exhibited differences in intensity from cell to cell in the early rudiment, while the reaction to the other antibodies was uniform throughout the rudiment. As lens differentiation progressed, immunofluorescence was restricted in all cases to the lens fiber area, up to and including Nieuwkas positive, however, for total lens crystallins. These results are at variance with earlier studies on lens development and the crystallins in wildtype (+/+) X. laevis, where a positive reaction for gamma and total crystallins could be detector total lens crystallins. That this divergence in the mutant is due to a pleiotropic effect or directly to the inductive failure of the endomesoderm to initiate melanogenesis, is discussed.

Albinism↗
PubMed1978

Edridge-Green Lecture, 1978. Visual disabilities of oculocutaneous albinism and their alleviation.

The visual disabilities of oculocutaneous albinism are discussed in the light of a series of 32 such patients seen in South-west Scotland between 1962 and 1978. Possible explanations for these defects are considered, with reference to an original series of light and electron microscopic sections from early embryos by Dr John Shaw-Dunn of the Department of Anatomy of Glasgow University which may afford clues to the relationship between the pigmentary and neurological aspects of the condition. Various forms of treatment which have been suggested are debated, and the author's own approach is described. Emphasis is laid on the social needs of the albino, and ways of meeting these are put forward.

Adolescent↗
PubMed1975

[Xanthofibrogranulomatosis, pontine glioma, multiple nevocytic nevi and albinism (authors transl)].

A case of retroperitoneal fibrosis with ureter compression is reported. Clinical picture and course were determined by the presence of an additional tumor (astrospongoblastoma) of the pons. Extraretroperitoneal tissue changes found at post mortem examination were shown histologically to be foreign tissues of the same type deposited in the retroperitoneal space (disseminated xanthofibrogranuloma). Possible connections between the disseminated xanthofibrogranuloma, the pontine tumor and an albinism also present and multiple nevocytic nevi of the skin are discussed.

Adult↗
PubMed1977

Detection of heterozygotes for tyrosinase-negative oculocutaneous albinism by hairbulb tyrosinase assay.

Five heterozygotes for ty-neg OCA had absent or markedly reduced hairbulb tyrosinase activity, when compared to normally pigmented control subjects. Clinically, all five were fully pigmented and could not be distinguished from the normal control subjects. It is proposed that the quantitative hairbulb tyrosinase assay can be used to detect heterozygotes for ty-neg OCA. A mechanism to explain the low levels of activity in the hairbulbs from heterozygotes is discussed.

Albinism↗
PubMed1979

Three variations of hairlessness associated with albinism in the laboratory rat.

The relationship of three variants of hairlessness, or hypotrichosis, in laboratory rats were examined morphologically, genetically and histologically. The results indicated that the recessive gene causing the fuzzy characteristic in Wistar Furth rats and genes responsible for two other hypotrichotic coat variants in albino rats were the same gene or closely linked genes. The genes were in Linkage Group I of the Norway rat and were closely associated with the albino gene (c), with a recombination percentage of approximately 18%. The hypotrichotic animals had fewer and smaller hair follicles, smaller hair shafts, and a reduction of medullated hair shafts.

Albinism↗
PubMed1979

[Immunochemical study of the water-soluble lens proteins in the embryo of Xenopus laevis with the mutation of periodic albinism].

The crystallins of ap mutants of Xenopus laevis have been studied in comparison with those of normal embryos and adults using the complex of immunochemical methods (immunoelectrophoresis, immunodiffusion, immunoadsorption, immunofluorescence, isoelectrofocusing with immunoidentification). The analysis was carried out with antisera to electrophoretic fractions of the mutant lens. 11 organ-specific antigens were found in the lens of both the normal and mutant animals. These proteins are heterogenous by electrophoretic mobility, isoelectrical point, antigenic and species specificity. Each class of crystallins contains antigens which are specific: a) for amphibians only, b) for lower vertebrates, c) for vertebrates in general. No qualitative differences were found between crystallins of the normal and mutant animals. Immunofluorescence analysis has shown that crystalins appear in the normal and mutant embryos practically at the same time. No significant differences in the appearance of specific immunofluorescence between the normal and mutant embryos were found (with various antisera). gamma-crystallins and, perhaps, a part of the primary lens fibers. Alpha-crystallins appear later. gamma-crystallins are first identified the synthesis of which manifests itself at the advanced developmental stages. The quantitative predominance of some beta--gamma-crystallins in the mutant lens detected by us (electrophoresis, isoelectrofocusing) is not related to their earlier synthesis in the embryogenesis.

Albinism↗