Absence Of Pigment In Skin Research Articles

Albinism in a raccoon Procyon lotor from Mexico

Albinism is defined as the complete absence of pigment in skin, hair, and eyes directly caused by a hereditary disorder in the production of melanin. This genetic abnormality is usually attributed to environmental factors such as low quality of habitat and inbreeding. In this note, we recorded a case of partial albinism in a raccoon (Procyon lotor) captured by poachers in the area known as Barranca de Matlacobatl, Municipality of Teocelo, Veracruz, Mexico. The specimen was recovered by the civil association Pro-Vida Silvestre Teocelotl and sheltered for a week under medical care. This is the second record in Mexico of a wild albino raccoon. Specifically, it was recorded particularly for a neotropical region of the center of the state of Veracruz, Mexico.

Functional in silico analysis of human tyrosinase and OCA1 associated mutations

Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. OCA1 exists in two forms: OCA1A and OCA1B. OCA1A is caused by a full loss of the human tyrosinase protein (Tyr), leading to an absence of pigment in skin, hair, and eyes, while OCA1B has reduced Tyr catalytic activity and pigment. The current understanding of the disease is hampered by the absence of information regarding the alterations of protein structure and the effects leading to either form of OCA1. Here, we used computational methods to find a general mechanism for establishing this link. Tyr and mutant variants were built through homology modeling, glycosylated in silico, minimized, and simulated using 100 ns molecular dynamics in water. For OCA1B mutants, cavity size is linked to ΔΔG values for mutants, suggesting that partial loss of Tyr is associated with the destabilizing effect of the EGF-like domain movement. In OCA1A, active site mutation simulations indicate that the absence of O2 leads to protein instability. OCA1B mutants are described in severity by the size of the cavity within the EGF-Tyr interface, while active site OCA1A mutants are unable to fully coordinate copper, leading to an absence of O2 and Tyr instability. In patients with known genotypes, free energy changes may help identify the severity of the disease by assessing either the allosteric effect of the EGF-Tyr cavity in OCA1B or the active site instability in OCA1A.

Carrier detection in X-linked ocular albinism of the Nettleship-Falls type by DNA analysis.

X-linked ocular albinism (XOA) is characterized by anomalies of the eyes and hypopigmentation or absence of pigment in skin, hair and eyes due to a hereditary inborn error of metabolism affecting the pigment cells. The gene of XOA of the Nettleship-Falls type (OA1) has been mapped to Xp22.3, and several closely linked RFLP loci have been identified. Linkage analysis and deletion mapping have established the marker gene order Xpter-STS-DX237-(OA1,DXS143,DXS85)-DXS1 6-DXS43-Xcen. Although the position of OA1 has yet not been fully resolved, we report on the first carrier detections in OXA of the Nettleship-Falls type by DNA analysis using markers which unquestionably flank OA1.

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

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: Our most important finding up till now is that normally pigmented people who do not look like albinos can in fact be albinos. 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. 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. 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.