Sharabi Alaa F., Goudar Raghavendra B.
University of Science and Technology
Manipal Hospital Bangalore
Alkaptonuria is one of a rare autosomal recessive genetic disorder, which results from the deficiency of homogentisate 1,2 dioxygenase (HGD). HGD gene is expressed in the liver, kidney, prostate, small intestine, and colon. This enzyme plays a role in the metabolism of tyrosine that converts homogentisic acid (HGA) into malate and acetoacetate. In the absence of HGD, homogentisic acid produced in excess by the liver oxidizes into ochronotic pigment polymer. Accumulation of this pigment in various tissues leads to systemic disease. This process is called ochronosis. Alkaptonuria was amongst the first genetic disorders in humans that found to follow the principles of Mendelian recessive inheritance. Historically, in 1908 it was used by Archibald Garrod in his Croonian lectures to illustrate the principles behind "inborn errors of metabolism." However, the Egyptian mummy Harwa believed to be the first clinical case of Alkaptonuria dating back as far as 1500 BC. The term alkaptonuria originated from the Arabic word "alkali." Also, Boedeker created the name in 1859 after he noticed unusual decreasing properties in patient urine. In 1866 ochronosis was discovered by Virchow, who noticed under microscopy when HGA pigment appeared to be a pale brownish yellow color (ochre-like).
黑尿症是一种罕见的常染色体隐性遗传病，由尿黑酸1,2-双加氧酶（HGD）缺乏引起。HGD基因在肝脏、肾脏、前列腺、小肠和结肠中表达。这种酶在酪氨酸代谢中发挥作用，将尿黑酸（HGA）转化为苹果酸和乙酰乙酸。在缺乏HGD的情况下，肝脏产生的过量尿黑酸氧化成褐黄病色素聚合物。这种色素在各种组织中的积累会导致全身性疾病。这个过程称为褐黄病。黑尿症是最早被发现遵循孟德尔隐性遗传原则的人类遗传病之一。历史上，1908年阿奇博尔德·加罗德在他的克罗尼安讲座中用它来说明“先天性代谢缺陷”背后的原理。然而，埃及木乃伊哈尔瓦被认为是最早可追溯到公元前1500年的黑尿症临床病例。术语“黑尿症”源于阿拉伯语单词“alkali”。此外，1859年博德克在注意到患者尿液中异常的减少特性后创造了这个名称。1866年，魏尔啸发现了褐黄病，他在显微镜下观察到尿黑酸色素呈现出浅棕黄色（类似赭石）。
