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At least 235 records · Page 13Linked to original sources
PubMed1991

Homozygous tyrosinase gene mutation in an American black with tyrosinase-negative (type IA) oculocutaneous albinism.

We have identified a tyrosinase gene mutation in an American black with classic, tyrosinase-negative oculocutaneous albinism. This mutation results in an amino acid substitution (Cys----Arg) at codon 89 of the tyrosinase polypeptide. The proband is homozygous for the substitution, suggesting that this mutation may be frequently associated with tyrosinase-negative oculocutaneous albinism in blacks.

Adult↗
PubMed1991

[Prenatal diagnosis of albinism].

Prenatal diagnosis of oculocutaneous albinism (OCA) was made in 1 of 6 pregnancies at risk examined during the 20th week of gestation. A skin biopsy was taken from the fetal scalp under ultrasonic screening. Light and electron microscopy studies were performed in each case to demonstrate melanin pigment and melanosomal development in the melanocytes of the hair bulbs and the epidermis. In 1 fetus albinism was diagnosed by the absence of melanin pigment and by the demonstration that melanosomes were only present in stages I and II. In the other 5 fetuses melanin pigment and mature melanosomes (up to stage IV) were demonstrated. The pregnancy with the albino fetus was interrupted and the diagnosis of OCA was confirmed at autopsy.

Albinism, Oculocutaneous↗
PubMed1986

Periodic alternating nystagmus associated with albinism.

We examined a 73-year-old woman with the rare association of albinism and (presumably) congenital periodic alternating nystagmus. The mechanism of the nystagmus in this case is uncertain. Anomalous retinogeniculate pathways have been documented in albino animals. Periodic alternating nystagmus might occur in some patients with albinism if there are also anomalies in the pathways conveying visual information to the cerebellum and brainstem.

Aged↗
PubMed1986

Zinc and copper metabolism in oculocutaneous albinism in the Caucasian.

Abnormalities in the zinc and copper metabolism have been described in some pigmentary retinopathies. In these eye disorders changes in the Retinal Pigment Epithelium are a common finding. Albinism is a manifestation of a metabolic disorder with abnormalities of pigment formation which also occurs in this mentioned retinal layer. Recently, we described abnormalities in the metabolism of these metals in black albino patients. In them, elevated values of ceruloplasmin were found. In the present study we performed a similar work among Caucasians. When both the Caucasian albino and control groups were compared, no statistical difference in the ceruloplasmin, serum zinc and copper and their concentration in urine was present. However, in 7 patients of the Caucasian albino group the serum zinc was distinctly elevated. The mean concentration of ceruloplasmin was high as well. No definitive correlation in regard to the positivity or negativity of tyrosinase was observed. Our findings may support our previous observations regarding albinism as a possible primary abnormality of zinc and copper metabolism.

Adolescent↗
PubMed1987

[Oculocutaneous albinism and brain atrophy].

We present a 4 months old female infant with oculocutaneous albinism and the clinical picture of motor retardation. Otherwise development appears to be normal. The finding of cerebral atrophy by CT scan is discussed as cerebral residual damage after perinatal hypoxia. A possible relation between albinism and CNS-disorder is described.

Albinism↗
PubMed1971

Investigation of a case of oculocutaneous albinism.

One conclusion reached from a study of a case of tyrosinase negative albinism was that the structure of melanizing apparatus was normal. Its regulation and ability to be stimulated was functionally normal also. The characteristic defect in albinism must be somewhere in the availability or inhibition of tyrosinase based on a genetically induced structural defect of the protein pattern.

Adult↗
PubMed1971

Genetic and biochemical evidence for two forms of oculocutaneous albinism in man.

Previous evidence for the existence of at least two genetically distinct forms of generalized oculocutaneous albinism was confirmed by the observation of a mating between two Negro albinos who had a normally pigmented daughter. Extensive blood typing provided no evidence for nonpaternity. Clinical and biochemical differences in the two types of albinism found in this family should permit easy recognition of these entities, although in Caucasians the two phenotypes may be quite similar.

Albinism↗
PubMed1971

Classification of albinism in man.

Genetic, tissue culture and ultrastructural studies demonstrate the heterogeneous nature of oculocutaneous albinism and a proposed classification based on these criteria is given. Six mutations are identified and the population frequencies of the common forms are determined. Some forms have, in addition to a pigment defect, abnormalities in platelets, glycolipids and chromosomes. In tyrosinase positive albinism, both in vitro and in vivo pigment formation can be induced by 1-tyrosine or 1-dopa.

Adolescent↗
PubMed1978

Oculocutaneous albinism associated with motor neuron disease.

The patient described is a 14-year-old girl who suffered from an oculocutaneous albinism. The developmental milestones were reached with some delay. Gradually she experienced fatiques, and wasting of the pelvic girdle muscles and weakness appeared. In suralis nerve biopsy sections no abnormalities were found. In muscle biopsy sections the characteristic findings of a primary central neuronal muscular atrophy were seen. Based on clinical and histopathological findings it may be stated that the patient is suffering from a motor neuron disease. The chance of the combined occurrence of oculocutaneous albinism and motor neuron disease can be estimated to be one out of 750 X 10(6), unless an incestuous relation is supposed.

Adolescent↗
PubMed1984

Genetic studies of ocular albinism in a large Virginia kindred.

Nettleship-Falls ocular albinism is an X-linked disorder characterized by variable degrees of impaired visual acuity, nystagmus, and macular hypoplasia in affected males and variable fundus pigmentation but normal acuities in females. Because of extreme variability in clinical manifestation, examination of family members may be necessary to confirm the diagnosis and is essential for genetic counseling purposes. This study reports the pedigree analysis and clinical findings in a large kindred from rural Virginia with 31 males reported to be affected among the 287 individuals in the pedigree. Clinical findings were quite variable, even within sibships, and some cases had been previously misdiagnosed, even in the presence of this remarkable family history. Linkage analysis in this family did not show the expected linkage with the Xg blood group. Examination of skin biopsies clearly indicated the cutaneous abnormality of giant pigment melanosomes (GPM) in both affected males and carrier females. Our use of light microscopy for detection of characteristic GPM may be easily employed as a carrier detection test, and therefore, provide the basis for accurate genetic counseling in families with ocular albinism.

Adolescent↗
PubMed1982

[Oculo-cutaneous tyrosinase-positive albinism].

In the present work, the authors discuss the participation of prostaglandins in inflammatory reaction due to U. V. light and the consequences of prostaglandins deficiency. A patient of algerian origin was observed: this 60 year old woman, exhibited an albinism thyrosinase positive and tolerated fairly well an exposure to the U. V. light despite her disease. For ten years she has presented face, neck and arms hyperkeratosis, for five years, arm actinic porokeratosis, and for two years back and face carcinomas. M. E. D. is higher than the standard value. The discussion is open on the fact that this M. E. D. rise might result from prostaglandins deficiency (PE E2 F2). Moreover prostaglandins deficiency increases epidermal multiplication and could account for hyperkeratosis and malignant change, especially so as the patient suffers from albinism and lives in a sunny country. The authors, besides, attempts to relate the other symptoms of this patient to the hypothetical deficiency of prostaglandins; absence of the melanosome maturation, delays in cicatrisation and perhaps immunity perturbations.

Aged↗
PubMed1995

Frequent intragenic deletion of the P gene in Tanzanian patients with type II oculocutaneous albinism (OCA2).

Type II oculocutaneous albinism (OCA2) is an autosomal recessive disorder in which the biosynthesis of melanin pigment is reduced in the skin, hair, and eyes. OCA2, which results from mutations of the P gene, is the most frequent type of albinism in African and African-American patients. OCA2 is especially frequent in Tanzania, where it occurs with an incidence of approximately 1/1,400. We have identified abnormalities of the P gene in each of 13 unrelated patients with OCA2 from Tanzania. One of these, a deletion of exon 7, is strongly predominant, accounting for approximately 77% of mutant alleles in this group of patients.

Albinism, Oculocutaneous↗
PubMed1994

Diverse mutations of the P gene among African-Americans with type II (tyrosinase-positive) oculocutaneous albinism (OCA2).

Type II (tyrosinase-positive) oculocutaneous albinism (OCA2) is an autosomal recessive disorder in which the biosynthesis of melanin pigment is reduced in the skin, hair, and eyes. OCA2, which we have shown results from mutations of the P gene in Caucasians, is the most prevalent type of oculocutaneous albinism in African and African-American patients with OCA. We have identified abnormalities of the P gene in seven unrelated African-American patients with OCA2, including three large deletions, two small in-frame deletions, and six different point mutations. None of these appears to be predominant among African-American patients with OCA2.

Adolescent↗
PubMed1994

[Study on genetic epidemiology of albinism].

Segregation analysis and consanguinity analysis were applied to 37 albinism families ascertained from Shandong province (P. R. China) to study the genetic heterogeneity of the disease. Our results show that albinism is an autosomal recessive disease with multilocus. The least number of the detrimental loci is 8, The average frequence of detrimental genes is 0.0023, and 3.83% individuals in general population are carriers. The incidence among the offsprings of the first cousin marriages would be 22 times higher than that in the general population.

Albinism↗
PubMed1994

Mutations of the tyrosinase gene in patients with oculocutaneous albinism from various ethnic groups in Israel.

We have analyzed the tyrosinase (TYR) gene in 38 unrelated patients with oculocutaneous albinism (OCA), derived from several different ethnic groups of the diverse population of Israel. We detected TYR gene mutations in 23 of the 34 patients with apparent type I (i.e., tyrosinase-deficient) OCA and in none of the patients with other clinical forms of albinism. Among Moroccan Jews with type IA (i.e., tyrosinase-negative) OCA, we detected a highly predominant mutant allele containing a missense substitution, Gly47Asp (G47D). This mutation occurs on the same haplotype as in patients from the Canary Islands and Puerto Rico, suggesting that the G47D mutation in these ethnically distinct populations may stem from a common origin.

Adolescent↗
PubMed1997

[Thrombocyte dysfunction in children with albinism].

Seven children with albinism were examined for haemorrhagic diathesis. In 6 patients coagulation screening tests (prothrombin time, activated partial thromboplastin time, thrombin time) were normal, in 1 patient prolongation of activated partial thromboplastin time due to mild factor XI deficiency was found. Platelet counts were in the reference range, however, the template bleeding time of 6 out of 7 patients was prolonged. Evaluation of platelet aggregation and secretion in a lumi-aggregometer demonstrated that only the child with normal bleeding time had normal platelet function, and 6 children with prolonged bleeding time had impaired aggregation and release reaction. Five out of these 6 patients had severe decrease of ATP secretion even when high dose of thrombin was used as agonist. The number of dens granules in the platelets of these patients, as measured by the uptake of mepacrine, was significantly less than in normal controls. These findings clearly suggested storage pool deficiency. In one of these patients storage pool deficiency was associated with mild factor XI deficiency. The high frequency of haemorrhagic diathesis in albino children emphasizes, the importance of the screening of patients with albinism for bleeding diathesis.

Adolescent↗
PubMed1976

Familial pulmonary fibrosis associated with oculocutaneous albinism and platelet function defect. A new syndrome.

A family was studied in which four siblings had oculocutaneous albinism. In three of these a platelet function defect characterized by poor response to collagen was found. The fourth had previously died from cryptogenic fibrosing alveolitis. Two of the survivors had cryptogenic fibrosing alveolitis and the third had physiological lung function disturbance. Bone marrow examination of one showed pigment laden macrophages (Hermansky-Pudlak Syndrome). Three other normally pigmented family members were found to have normal platelets and no evidence of cryptogenic fibrosing alveolitis, although one had pulmonary disease attributable to occupational dust exposure. To elucidate the aetiological factors involved, three unrelated normally pigmented patients with known platelet function defect were studied. One proved to have cryptogenic fibrosing alveolitis. Four unrelated albinos were also studied and had normal lungs and platelets. It is suggested that, in addition to the known association between platelet function defect and albinism, there is an association between a platelet function defect and cryptogenic fibrosing alveolitis.

Adenosine Diphosphate↗