Zdrojewicz Zygmunt, Kowalik Małgorzata, Jagodziński Adam
Medical University of Wrocław Poland: Faculty of Postgraduate Medical Training, Department and Clinic of Endocrinology, Diabetology and Isotope Therapy, Faculty of Medicine.
Medical University of Wrocław Poland: Students of Medical Faculty.
Pol Merkur Lekarski. 2016 Dec 22;41(246):306-309.
Only 1-2% of people is red-headed but in the Russian Udmurt Republic or United Kingdom they can be met more often. A specific variant of MC1R gene (R allele) is responsible for the red hair. The gene encodes a receptor for melanocortins. These substances stimulate melanocytes to product melanin- a dye of the skin which is transported to keratinocytes. It protects a cellular nucleus from ultraviolet radiation. Melanin has two types: eumelanin which is dark brown or even black and red/orange pheomelanin. The second one is mostly observed in red-headed which is caused by R allele. The DNA damage occurs more easily because of worse protecting ability of pheomelanin. Moreover this allele is connected with inefficient DNA repair. People with R allele have not only flaming red hairstyle but also very fair skin (often with freckles) and blue eyes. Unfortunately this phenotype is more exposed to harmful effects of UV rays. It means that too extensive exposition to solar light leads to sunburn and development of cancerous skin diseases with melanoma as the worst. R allele is a recessive variant of the gene so only in homozygous persons this characteristic phenotype is observed. Nevertheless blond- or auburn-haired carriers of this allele are also more prone to develop carcinomas. The red-headed also differ from the others in sensitivity to anaesthetics, what is shown by increased MAC. On the other hand these persons less often suffer from vitamin D deficiency. The aim of the article is to present facts and myths of red-headed.
只有1 - 2%的人是红头发，但在俄罗斯的乌德穆尔特共和国或英国，红头发的人更为常见。MC1R基因的一种特定变体（R等位基因）导致了红头发。该基因编码一种黑素皮质素受体。这些物质刺激黑素细胞产生黑色素——一种皮肤色素，会被转运到角质形成细胞中。它保护细胞核免受紫外线辐射。黑色素有两种类型：深棕色甚至黑色的真黑素，以及红色/橙色的褐黑素。第二种主要出现在红头发的人身上，这是由R等位基因引起的。由于褐黑素的保护能力较差，DNA损伤更容易发生。此外，这个等位基因与低效的DNA修复有关。携带R等位基因的人不仅有火红的发型，还有非常白皙的皮肤（通常有雀斑）和蓝色眼睛。不幸的是，这种表型更容易受到紫外线的有害影响。这意味着过度暴露在阳光下会导致晒伤和皮肤癌的发生，其中最严重的是黑色素瘤。R等位基因是该基因的隐性变体，所以只有在纯合子个体中才能观察到这种典型的表型。然而，携带这个等位基因的金发或赤褐色头发的人也更容易患癌症。红头发的人对麻醉剂的敏感性也与其他人不同，最低肺泡有效浓度（MAC）的增加就表明了这一点。另一方面，这些人患维生素D缺乏症的情况较少。本文的目的是介绍关于红头发人群的事实与误解。
