Ochronosis – a rare metabolic disease (original) (raw)
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A late and difficult diagnosis of ochronosis
Journal of medicine and life
Alkaptonuria is a rare autosomal recessive disorder of metabolism caused by deficiency of homogentisic acid oxidase and resulting in accumulation of homogentisic acid in collagenous structures. This causes the classic clinical triad: (1) homogentisic aciduria (urine blackens on standing when oxidized or alkalinized); (2) eumelanin-like pigmentation of skin, sclera, cartilages, etc and (3) degenerative ochronic arthropathies usually in the fourth decade of life. Other important but more rare consequences of alkaptonuric ochronosis are cardiovascular and urinary tract involvement. We present a case of ochronosis with multiple visceral involvement: skin (fingers, ear sclera), severe spondylarthropaty with extensive calcifications of intervertebral discs and reduced mobility, osteoarthritis of both knees, right hip ostonecrosis, cardiovascular involvement (severe stenosis and insufficiency of aortic valve that) and urinary tract involvement (nephrolitiasis)
Skin pigmentation, a window to diagnose Alkaptonuria: a very rare entity
International Journal of Research in Medical Sciences, 2017
Alkaptonuria (AKU) or endogenous ochronosis is a very rare inborn error of tyrosine metabolism inherited by autosomal recessive mode. There is complete absence of homogentisic acid oxidase enzyme which results in accumulation of homogentisic acid in cartilaginous connective tissue thus produces ochronotic clinical manifestations. Here we reported a 36 year old woman with bluish pigmentation of pinnae, index fingers (lateral aspect), nails, teeth and sclera. Detailed clinical and investigative workup was done to diagnose patient. Skin biopsy showed changes of ochronosis and urine examination revealed detectable level of homogentisic acid. Classical ocular findings, ochronosis on clinical and HPE and positive urinary tests for homogentisic acid confirmed the diagnosis of alkaptonuria. The highlight of our case is that an asymptomatic patient was detected early by ochronosis prior to development of musculoskeletal or cardiac complications.
Journal of cellular …, 2012
Alkaptonuria (AKU) results from defective homogentisate1,2-dioxygenase (HGD), causing degenerative arthropathy. The deposition of ochronotic pigment in joints is so far attributed to homogentisic acid produced by the liver, circulating in the blood and accumulating locally. Human normal and AKU osteoarticular cells were tested for HGD gene expression by RT-PCR, mono- and 2D-Western blotting. HGD gene expression was revealed in chondrocytes, synoviocytes, osteoblasts. Furthermore, HGD expression was confirmed by Western blotting, that also revealed the presence of five enzymatic molecular species. Our findings indicate that AKU osteoarticular cells produce the ochronotic pigment in loco and this may strongly contribute to induction of ochronotic arthropathy. J. Cell. Physiol. 227: 3254–3257, 2012. © 2011 Wiley Periodicals, Inc.