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Autosomal recessively inherited ocular albinism. A new form of ocular albinism affecting females as severely as males.

A new form of ocular albinism, autosomal recessively inherited ocular albinism (AROA), was studied in seven females and two males from five unrelated Caucasian kindreds. Affected patients have the impaired vision, translucent irides, congenital nystagmus, photophobia, albinotic fundi with hypoplasia of the fovea, and strabismus that are also found in X-linked ocular albinism (XOA). Unlike XOA, however, this form of ocular albinism is inherited as an autosomal recessive trait, with females affected as severely as males. Obligate heterozygotes of AROA lack the ocular abnormalities that are present in females heterozygous for XOA. Also, skin and hairbulb biopsy specimens do not reveal any abnormalities in patients with AROA, whereas giant pigment granules are found in patients heterozygous and hemizygous for XOA. The recognition of this disorder is imperative for proper diagnosis and responsible genetic counseling.

Adult

X-linked ocular albinism: a family containing a manifesting heterozygote, and an affected male married to a female with autosomal recessive ocular albinism.

A pedigree of X-linked ocular albinism is presented containing nine affected males and 10 heterozygous females. One carrier female showed ocular changes similar to those of affected males. She is considered to be a manifesting heterozygote, a situation explained by the Lyon hypothesis. One affected male married a female with autosomal recessive ocular albinism and produced one daughter with the fundus changes of the carrier state of X-linked ocular albinism, and one son with normal eyes. The daughter did not show any evidence of the additive effect of the two different genes for X-linked and autosomal recessive ocular albinism.

Albinism

Ocular albinism in a male with del (6)(q13-q15): candidate region for autosomal recessive ocular albinism?

We describe a boy with an interstitial deletion of 6(q13-q15) and include "coarse" facial features, upslanting palpebral fissures, thin vermilion border of the upper lip, elongated philtrum, developmental delay, and profound hypotonia. The child's eye findings, pedigree, paucity of maternal ocular changes, and lack of melanin macroglobules in the skin suggest that this individual's phenotype is clinically similar to that of autosomal recessive ocular albinism. Though it is possible that this deletion and his ophthalmic disorder are coincidental, we postulate that the ocular albinism may be due to hemizygosity for a paternally derived ocular albinism gene located on chromosome 6 in the region q13-q15. This patient's deletion is secondary to a recombination of a maternal intrachromosomal inverted insertion of this region. Of the 7 reported 6q1 deletions, this is the only case that is due to a familial chromosome rearrangement.

Albinism, Ocular

X-linked ocular albinism in Blacks. Ocular albinism cum pigmento.

X-linked ocular albinism can be an unsuspected cause of congenital nystagmus in blacks. In this study, eight of ten black ocular albinos from two kindreds had nonalbinotic, moderately pigmented fundi and no transillumination of the iris. We refer to this paradoxical condition as "ocular albinism cum pigmento." The only constant ophthalmoscopic feature was a foveal hypoplasia. Biopsy of clinically normal skin to demonstrate giant pigment granules is the most accurate means of diagnosis.

Adolescent

[Eumelanin and pheomelanin contents in hairs of healthy Japanese and patients with oculocutaneous albinism, and 5-S-cysteinyldopa and 5-hydroxy-6-methoxyindole-2-carboxylic acid levels in urine of oculocutaneous albinism].

The contents of eumelanin and pheomelanin in the scalp hairs of 4 Japanese patients with total albinism (3 tyrosinase-positive and one negative) and 100 healthy Japanese were measured by the melanin microquantitation method of Ito and Fujita. The urinary 5-S-Cysteinyldopa (5-S-CD) and 5-Hydroxy-6-Methoxyindole-2-Carboxylic acid (5H6MI2C) contents in the 4 albino subjects were also determined. Our findings included that (1) Regardless of ge, black hairs of all the healthy subjects contained phemelanin at a level of about 5% of the total melanin contents. The hair color of the 3 tyrosinase-positive subjects was pale-yellow, and their hairs contained only pheomelanin. The hair color of the one tyrosinase-negative subject was white, and neither eumalanin nor pheomelanin could be detected. (2) Urinary 5H6M12C, an indicator of eumelanin production in the body, could not be detected in either the tyrosinase-positive or tyrosinase-negative subjects, while the urinary 5-S-CD content of the tyrosinase-negative subject was much lower than that of the tyrosinase-positive subjects. These results suggested that the yellow hair color of patients with tyrosinase-positive albinism is attributable to the production of only pheomelanin and that the urinary 5-S-CD content does not necessarily reflect the ability to produce melanin.

Adolescent

Albinism, or the NOACH syndrome (the book of Enoch c.v. 1-20).

UNLABELLED: After a 4-year multidisciplinary study of albinism our findings will be presented here. Over a hundred albinos were examined, together with their heterozygote family members. Given this substantial patient and subject sample we were provided with the opportunity to: evaluate the results of standard diagnostic procedures, for example pedigree analysis, ocular and clinical examination; determine the diagnostic value of biochemical, and ultrastructural tests; and develop a new and viable albino diagnostic protocol, particularly for electrophysiological examination. In the conclusions the following subjects are in order: DIAGNOSIS: Our most important finding up till now is that normally pigmented people who do not look like albinos can in fact be albinos. DIFFERENTIAL DIAGNOSIS: It appears that patients with autosomal recessive albinism can be normally pigmented, and patients with X-linked albinism can be severely hypopigmented. We therefore propose to abandon the terms oculo-cutaneous albinism (OCA), and X-linked ocular albinism (XOA), and use the terms autosomal recessive albinism, and X-linked albinism instead. X-linked albinism Forsius-Eriksson type (XOAF): We assume that XOAF does not represent a true form of albinism. CLASSIFICATION: Our results indicate that the phenotypical albino classification, which was a base for Witkop et al. (1978) to also obtain a genetical classification, supported by the hairbulb test, has not proved to be useful for the classification of tyrosinase negative (TNOCA), tyrosinase positive oculocutaneous albinism (TPOCA), and autosomal recessive ocular albinism (AROA) as genetically distinct forms. Prevalence: Our prevalence estimate for all forms of albinism is at least 1:15,000, about 10% of the albinos have X-linked albinism. DEFINITION: We want to modify the albino definition as a hereditary and congenital inborn error of metabolism related to the pigment cell, and resulting in a systemic disorder that is characterized by anomalies of eyes, and hypopigmentation in most cases or absence of pigment in skin, hair, and eyes, and of which the neuro-anatomical consequences are the most characteristic.

Albinism

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

Red or rufous albinism in southern Africa.

Red or rufous albinism is a rare type of oculocutaneous albinism described, but not as yet fully investigated, in Africa and New Guinea. Twelve rufous albino subjects from 10 families participated in this preliminary study. The prevalence of rufous albinism was found to be approximately one in 8,580 among school children in the negroid population. The combination of the unusual red skin colour, ginger to reddish hair colour, low susceptibility to sun damage, and minimal visual problems, in affected individuals, suggested that they form a group which is distinct from the brown and other types of albinism. The mode of inheritance was found to be recessive. Tyrosinase assays showed that rufous albinos are tyrosinase positive and on electron microscopy studies normal melanosomes and melanocytes were observed in hair bulbs and skin. Visual evoked potential testing did not show the gross decussation abnormalities of the optic pathway detected in other types of albinism. Rufous albinism might be at one end of the spectrum of types of oculocutaneous albinism and, because affected people have such mild symptoms, their inclusion in this group might be debatable.

Adolescent

Variable expression of vision in sibs with albinism.

Oculocutaneous albinism is defined by the presence of cutaneous and ocular hypopigmentation, the latter associated with nystagmus, iris transillumination, reduced retinal pigment, foveal hypoplasia, and misrouting of the optic fibers at the chiasm. The visual acuity is variable but almost always reduced. We report on two brothers with oculocutaneous albinism and markedly different visual acuity. One brother has a visual acuity of 20/100, while the second has similar cutaneous pigmentation and visual acuity of 20/20 and had not previously been recognized as having oculocutaneous albinism. Both brothers have foveal hypoplasia and misrouting of the optic fibers at the chiasm. Biochemical analysis suggests that this is a tyrosinase-related type of oculocutaneous albinism. This study demonstrates that careful observation of foveal development in relatives with normal vision is necessary to detect all individuals with albinism in a family. A suspected diagnosis of albinism may be confirmed when the visual-evoked potentials show excessive decussation of the optic fibers at the chiasm.

Adolescent

Albinism and Hermansky-Pudlak syndrome in Puerto Rico.

Five types of oculocutaneous albinism and two types of ocular albinism were found among 349 Puerto Rican albinos. The most prevalent type of albinism was the Hermansky-Pudlak syndrome (HPS). HPS was observed in five of every six albinos in Puerto Rico. The prevalence of HPS was highest in the northwestern quarter of the island, affecting approximately one in 1,800 persons, and approximately one in 22 are carriers of the gene. HPS is an autosomal recessively inherited triad of a tyrosinase-positive type of albinism, a hemorrhagic diathesis due to storage pool deficient platelets and accumulation of ceroid in tissues. The pigmentary phenotype of HPS albinos resembled that of any other type of oculocutaneous or ocular albinism. The most reliable method of diagnosing HPS is by a deficiency of platelet dense bodies observed by electron microscopy. The accumulation of ceroid in the tissues is associated with fibrotic restrictive lung disease and granulomatous enteropathic disease. The enteropathic disorder resembles Crohn's disease and with few exceptions, had its onset after 13 years of age. The major causes of death were fibrotic restrictive pulmonary disease, hemorrhagic episodes and sequelae of granulomatous enteropathic disease. Menometrorrhagia was common in women with HPS. No immune deficiency was found in HPS patients. The majority of patients with HPS had visual acuities of 20/200 or worse and consequently were legally blind. Albinos of all types, including HPS, lacked binocular vision due to nearly complete crossing of the optic tracts.

Albinism, Ocular

Albinism.

Albinism is the term applied to a heterogeneous group of genetically determined disorders characterized by hypopigmentation and affecting the eyes. After describing the clinical features of albinism in general, the authors discuss the various forms of oculocutaneous albinism, ocular albinism, and albinoidism that are of interest to the ophthalmologist. Emphasis is placed on the ocular features of each form. The visual pathway abnormalities and the clinical management of albinism are discussed.

Albinism

Hypoplastic corpus callosum in ocular albinism: indication of a global disturbance of neuronal migration.

Ocular albinism is distinguished from the more common oculocutaneous albinism by the presence of normal pigmentation of skin and hair in the former condition. Recent studies of ocular albinism have shown that the hypopigmentation of the optic fundus is associated with a number of anomalies of neuronal wiring involving the visual system. We present a patient with ocular albinism who also has a hypoplastic corpus callosum as determined by analysis of midsagittal magnetic resonance imaging scans. Previous studies of the hypoplastic corpus callosum indicate that this anomaly is a defect in neuronal migration as well. The finding of a hypoplastic corpus callosum in a patient with ocular albinism suggests a more generalized defect in neuronal migration not limited to the visual system.

Abnormalities, Multiple

Albinism.

Genetic abnormalities of the melanin pigment system in which the synthesis of melanin is reduced or absent are called albinism. The reduction in melanin synthesis can involve the skin, hair follicle, and eye, resulting in oculocutaneous albinism, or can be localized primarily to the eye, resulting in ocular albinism. Approximately 1 in 17,000 individuals in the United States has oculocutaneous albinism, and more than 1 per cent of the population are heterozygous for a gene producing albinism.

Albinism

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

Albinism. Recent advances.

There have recently been several fundamental advances in our understanding of albinism, both in animals and in man. These advances have been in the division of oculocutaneous albinism into tyrosinase-negative and tyrosinase-positive forms, the demonstration of a widespread disturbance in the structure of melanosomes in X-linked ocular albinism, the description of the condition now known as autosomal recessive ocular albinism, and a peculair anatomical abnormality of the visual pathways which appears to be present in all forms of oculocutaneous and ocular albinism. Evidence has been presented which confirms that the retinogeniculate anomaly in human albinos is similar to that in animals, and it has recently been suggested that there may be two major patterns of geniculocortical projected in man, as there are in the Siamese cat.

Albinism

A high-frequency albinism variant on the gulf coast of Papua.

An apparently recessively inherited albinism variant characterized by skin tanning, light but not white hair, uniformly pigmented irides varying in colour from hazel to dark brown, slight nystagmus, divergent strabismus, mild hyperkeratosis and only slight or absent photophobia, occurs among the Elema-speaking peoples of the Gulf Province of Papua New Guinea at frequencies indicating that the gene which produces it is polymorphic. It is readily distinguishable from both classical types of albinism, from the "redskin" variant also found in Papua New Guinea, and from the "yellow mutant" albinism of North America. The differences from the African types of "albinoidism" or "partial albinism" are less marked, and it may represent a similar mutation with simply a different distribution of the melanosomes in the two peoples, Allelism, or lack of it, with classical tyrosinase-positive albinism has not been determined.

Adult