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Insight (American Society of Ophthalmic... 2009Albinism is an inherited disorder characterized by a reduction or absence of melanin in the hair, skin, and/or eyes. Tyrosinase, a major enzyme required in the... (Review)
Review
Albinism is an inherited disorder characterized by a reduction or absence of melanin in the hair, skin, and/or eyes. Tyrosinase, a major enzyme required in the production of melanin, is deficient to varying degrees in albinism. Albinism can be divided into one of two broad categories, oculocutaneous and ocular albinism, based on the involvement of hair, skin and the eyes versus only the eyes, respectively. Common ocular findings include reduced visual acuity, refractive errors, iris transillumination, nystagmus, foveal hypoplasia, fundus hypopigmentation and misrouting of optic nerve fibres at the chiasm. Eye care professionals can play an important role when tending to patients with albinism. This article will provide the reader with an overview of the etiology of albinism, the prevalence, clinical manifestations and management options.
Topics: Albinism, Oculocutaneous; Genetic Predisposition to Disease; Genotype; Global Health; Humans; Melanins; Pigment Epithelium of Eye; Prevalence; Prognosis
PubMed: 19534229
DOI: No ID Found -
International Journal of Ophthalmology 2023
PubMed: 36935786
DOI: 10.18240/ijo.2023.03.23 -
Indian Journal of Ophthalmology May 2023
Topics: Humans; Albinism, Ocular; Retina; Visual Acuity; Choroid; Tomography, Optical Coherence
PubMed: 37203000
DOI: 10.4103/IJO.IJO_3059_22 -
International Journal of Molecular... Sep 2016To investigate whether () is differentially expressed in the skin of mice with different coat colors and to determine its correlation with coat color establishment in...
To investigate whether () is differentially expressed in the skin of mice with different coat colors and to determine its correlation with coat color establishment in mouse, the expression patterns and tissue distribution characterization of in the skin of mice with different coat colors were qualitatively and quantitatively analyzed by real-time quantitative PCR (qRT-PCR), immunofluorescence staining and Western blot. The qRT-PCR analysis revealed that mRNA was expressed in all mice skin samples tested, with the highest expression level in brown skin, a moderate expression level in black skin and the lowest expression level in gray skin. Positive OA1 protein bands were also detected in all skin samples by Western blot analysis. The relative expression levels of OA1 protein in both black and brown skin were significantly higher than that in gray skin, but there was no significant difference between black and brown mice. Immunofluorescence assays revealed that OA1 was mainly expressed in the hair follicle matrix, the inner and outer root sheath in the skin tissues with different coat colors. To get further insight into the important role of in the melanocytes' pigmentation, we transfected the into mouse melanocytes and then detected the relative expression levels of pigmentation-related gene. Simultaneously, we tested the melanin content of melanocytes. As a result, the overexpression of significantly increased the expression levels of (), (), () and (). However, the () level was attenuated. By contrast, the level of () was unaffected by overexpression. Furthermore, we observed a significant increase in melanin content in mouse melanocyte transfected . Therefore, we propose that may participate in the formation of coat color by regulating the level of and the number, size, motility and maturation of melanosome.
PubMed: 27690000
DOI: 10.3390/ijms17101596 -
Archivos de La Sociedad Espanola de... Jun 2019A 12 year-old boy who consulted due to nystagmus and low vision from birth. His mother also consulted for low vision of the right eye since she was a child, which...
A 12 year-old boy who consulted due to nystagmus and low vision from birth. His mother also consulted for low vision of the right eye since she was a child, which worsened recently. The physical examination revealed no alterations in skin and hair pigmentation. In the examination of the anterior segment of the child, areas of slight circumferential hypopigmentation were observed in the iris in both eyes. The fundus examination revealed a choroidal fundus due to the absence of melanin in the retinal pigment epithelium. In the autofluorescence, an absence of physiological macular hypo-autofluorescence was observed and, in optical coherence tomography, foveal hypoplasia was observed in both eyes. In the ocular fundus examination of the mother, slight macular pigmentary changes were observed in the right eye, with hyperpigmented radiated spots in the retinal periphery of both eyes, which were hypo-autofluorescent in the wide-field autofluorescence. In the optical coherence tomography of the right eye, a cavitation of the outer retinal layers was observed in the fovea. The genetic study by nucleotide sequencing was performed on the mother and the child. In the mutation found in the GPR143 gene, the son was hemizygous and the mother was heterozygous. X-linked ocular albinism was diagnosed and the genetic counselling was carried out. Ocular albinism linked to X is the most frequent genetic variant of this disease. Peripheral pigment alterations in heterozygous mothers have been previously described in the literature, but there are no reports of cavitations in the external retinal layers using optical coherence tomography.
Topics: Albinism, Ocular; Child; Eye Proteins; Humans; Male; Membrane Glycoproteins; Mutation; Optical Imaging; Tomography, Optical Coherence
PubMed: 31103373
DOI: 10.1016/j.oftal.2019.01.006 -
Lancet (London, England) Jun 1968
Topics: Albinism; Eye Diseases; Female; Heterozygote; Humans; Male; Pedigree; Recombination, Genetic; Sex Chromosomes; Vision Tests
PubMed: 4172140
DOI: 10.1016/s0140-6736(68)92295-2 -
Lancet (London, England) May 1971
Topics: Albinism; Blood Group Antigens; Eye Diseases; Humans; Recombination, Genetic; Sex Chromosomes
PubMed: 4102999
DOI: 10.1016/s0140-6736(71)91636-9 -
Documenta Ophthalmologica. Advances in... Oct 2014In routine clinical evaluation of optic neuritis and chiasmal tumours, pattern electroretinography and visual evoked potentials (VEPs) to pattern-reversal stimulation... (Review)
Review
BACKGROUND AND METHODS
In routine clinical evaluation of optic neuritis and chiasmal tumours, pattern electroretinography and visual evoked potentials (VEPs) to pattern-reversal stimulation are useful examinations. Similarly, in achiasmia and ocular albinism, VEPs to flash and pattern-onset stimulation provide relevant information.
RESULTS
The role of visual electrophysiology in these diseases is to assess potential dysfunction of the visual pathway: (a) at the acute stage of optic neuritis, to determine the magnitude of conduction block of the optic nerve fibres; (b) at the clinical recovery stage of optic neuritis, to determine optic nerve conduction delay due to demyelination, and to follow possible remyelination; (c) at the recovery of optic neuritis when visual acuity does not normalise, to define loss of optic nerve fibres and retrograde degeneration of retinal ganglion cells; (d) in tumours at the chiasm, to detect abnormal conduction along the crossed and/or uncrossed fibres; and (e) in achiasmia or albinism, which are both congenital disorders associated with nystagmus, to detect achiasmia and absence of or reduced optic nerve fibre decussation at the chiasm, or to detect ocular albinism and excess of optic nerve fibre decussation at the chiasm. In optic neuritis, two recent examinations have been used to detect retrograde axonal degeneration: photopic negative response of the electroretinogram, to assess dysfunction of ganglion cell axons; and optic coherence tomography, to measure thinning of the retinal nerve fibre layer. In optic neuritis, multifocal VEPs provide a promising clinical examination, because this can show areas that are associated with normal or abnormal optic nerve fibre function.
CONCLUSIONS
Visual electrophysiology defines function of the visual pathway and is relevant: (1) in optic neuritis, when visual acuity does not recover well; (2) in tumours of the chiasm with normal visual fields, as in paediatric patients who cannot adequately perform perimetry; and (3) in children with congenital nystagmus and suspected achiasmia or ocular albinism.
Topics: Albinism, Ocular; Electrophysiology; Electroretinography; Evoked Potentials, Visual; Eye Abnormalities; Humans; Optic Chiasm; Optic Nerve Neoplasms; Optic Neuritis
PubMed: 24962442
DOI: 10.1007/s10633-014-9448-8 -
American Journal of Medical Genetics.... Jul 2018Ocular albinism type 1 (OA1) is caused by mutations in the GPR143 gene located at Xp22.2. The manifestations, which are due to hypopigmentation, are confined to the eyes...
Ocular albinism type 1 (OA1) is caused by mutations in the GPR143 gene located at Xp22.2. The manifestations, which are due to hypopigmentation, are confined to the eyes and optic pathway. OA1 associated with late-onset sensorineural hearing loss was previously reported in a single family and hypothesized to be caused by a contiguous gene deletion syndrome involving GPR143 and the adjacent gene, TBL1X. Here, we report on a family with OA1, infertility, late-onset sensorineural hearing loss, and a small interstitial Xp microdeletion including the GPR143, TBL1X, and SHROOM2 genes. In addition, we re-examined a patient previously described with OA1, infertility and a similar Xp deletion with audiologic follow-up showing a late-onset sensorineural hearing loss. Our results raise an intriguing question about the possibility for TBL1X (absence) involvement in this type of hearing loss. However, our study cannot claim a causative relationship and more convincing evidence is needed before the hypothesis can be accepted that TBL1X could be involved in late-onset sensorineural hearing loss and that ocular albinism with late-onset sensorineural hearing loss can present itself as a contiguous gene deletion/microdeletion syndrome. The finding of infertility in all affected male patients demonstrates that this deletion, including the SHROOM2 gene, may be a potentially causative X-linked genetic factor of male infertility.
Topics: Adult; Aged; Albinism, Ocular; Eye Proteins; Female; Gene Deletion; Genetic Diseases, X-Linked; Hearing Loss, Sensorineural; Humans; Infertility; Male; Membrane Glycoproteins; Membrane Proteins; Middle Aged; Mutation; Pedigree; Transducin
PubMed: 30160833
DOI: 10.1002/ajmg.a.38836 -
Seminars in Cutaneous Medicine and... Mar 1997Albinism connotes a large group of genetic disorders that are characterized by diminished ocular and oftentimes cutaneous pigmentation. These disorders are generally... (Review)
Review
Albinism connotes a large group of genetic disorders that are characterized by diminished ocular and oftentimes cutaneous pigmentation. These disorders are generally subclassified as oculocutaneous albinism (OCA) or ocular albinism (OA) based on the extent of their effects on the pigmentation of the skin and hair. Sometimes, different mutations in the same gene can cause OCA or OA.
Topics: Albinism; Albinism, Ocular; Albinism, Oculocutaneous; Eye; Genetic Linkage; Hair; Humans; Mutation; Skin Pigmentation; Tyrosine; X Chromosome
PubMed: 9125762
DOI: 10.1016/s1085-5629(97)80032-6