1/84. Ocular ochronosis in alkaptonuria patients carrying mutations in the homogentisate 1,2-dioxygenase gene.AIMS: To assess the involvement of the recently identified human homogentisate 1,2-dioxygenase gene (HGO) in alkaptonuria (AKU) in two unrelated patients with ochronosis of the conjunctiva, sclera, and cornea. methods: A mutation screen of the entire coding region of the HGO gene was performed using single stranded conformational analysis after polymerase chain reaction with oligonucleotide primers flanking all 14 exons of the HGO gene. Fragments showing aberrant mobility were directly sequenced. RESULTS: Two homozygous missense mutations, L25P and M368V, were identified, each of which leads to the replacement of a highly conserved amino acid in the HGO protein. CONCLUSIONS: The authors describe a novel mutation, L25P, in the German population and bring to 18 the total number of known HGO mutations.- - - - - - - - - - ranking = 1keywords = ochronosis (Clic here for more details about this article) |
2/84. Hereditary ochronosis: hyperpigmented skin overlying cartilaginous structures.Hereditary ochronosis, or alkaptonuria, results from deficiency of homogentisic acid oxidase. It is an autosomal recessive condition found in geographically isolated populations. The excess homogentisic acid deposits in collagenous structures, leading to unusual pigmentation of the skin overlying cartilaginous structures, but on occasion pigment is also seen in the sclera, in sweat after oxidation, and classically, in urine when left standing at room temperature. This case report highlights the pathogenesis and expression of this rare disorder.- - - - - - - - - - ranking = 1keywords = ochronosis (Clic here for more details about this article) |
3/84. Ochronotic arthropathy: case report and review of the literature.Alkoptonuria is an inherited metabolic disorder which is associated with various systemic abnormalities and related to the deposition of homogentisic acid pigment in connective tissues. These pigmentary changes are termed "ochronosis". We describe two patients with ochronotic arthropathy who presented with progressive and advanced degenerative changes in the lumbo-sacral spine. The literature, differential diagnosis and management of this rare condition are reviewed in this article. Management is usually conservative, but replacement surgery may be offered for severely affected major joints.- - - - - - - - - - ranking = 0.2keywords = ochronosis (Clic here for more details about this article) |
4/84. Aortic stenosis in endogenous ochronosis.Endogenous ochronosis, a rare inherited disease of tyrosine metabolism, is caused by a deficiency of the enzyme, homogentisic acid oxidase, and may lead to cardiovascular involvement seen most frequently as aortic valve stenosis. We report the case of a patient with generalized ochronosis who developed cardiovascular symptoms due to aortic valve stenosis and who underwent aortic valve replacement.- - - - - - - - - - ranking = 1.2keywords = ochronosis (Clic here for more details about this article) |
5/84. ochronosis: an unusual finding at aortic valve replacement.The condition known as ochronosis refers to the accumulation of oxidized homogentisic acid in the connective tissues of alkaptonuric patients. The diagnosis is usually made from the triad of degenerative arthritis, ochronotic connective tissue pigmentation and urine that turns dark brown or black on alkalinization. Cardiovascular disease is a less well appreciated aspect of this disorder. A patient with ochronosis of his stenotic aortic valve is reported. The role of the pigment in the genesis of the valve degeneration is discussed.- - - - - - - - - - ranking = 0.4keywords = ochronosis (Clic here for more details about this article) |
6/84. A morphological study of bone and articular cartilage in ochronosis.An ochronotic femoral head has been studied morphologically under the light and the electron microscope. Its articular cartilage showed the alterations already reported in the literature, mainly consisting of erosions of the surface, pigment accumulation in chondrocytes and intercellular matrix, chondrocyte degeneration, the formation of pigmented, calcified and uncalcified microshards, and the presence of granulation tissue with macrophagic cells. The changes in bone were less severe than those in cartilage. Pigment was present in the calcified matrix. This did not seem to disturb the organization of the bone tissue, although it was diffusely osteoporotic, perhaps because of limb disuse. The preservation of calcified matrix might depend on the fact that its collagen fibrils are encrusted by mineral substance, which avoids the dangerous effects that the deposition of ochronotic pigment induces in the fibrils of soft connective tissues. On the other hand, the newly formed osteoid matrix remains uncalcified for too short a time to be modified by the pigment. Diffuse or granular pigmentation was found in a few osteocytes, while several of them were condensed or reduced to cellular fragments. bone resorption often occurred near these osteocytes. However, this did not seem to alter the degree of bone remodelling, possibly because of the relatively low numbers of degenerated or dead osteocytes. Pigment was also contained in the cytoplasmic vacuoles of otherwise active osteoclasts, whereas it was not found in osteoblasts. On the whole, ochronosis in bone seems to induce the same changes as in other connective tissues. However, their severity appears to be limited by calcification, which prevents modifications in collagen fibrils, and by bone remodelling, which to some extent eliminates the oldest, pigment-richest parts of the tissue.- - - - - - - - - - ranking = 1keywords = ochronosis (Clic here for more details about this article) |
7/84. Exogenous ochronosis.ochronosis is an uncommon condition characterized by yellow-brown pigment deposits in the dermis. It occurs in exogenous and endogenous forms. We report a case of exogenous ochronosis in a Hispanic woman and discuss the different forms of this condition. We treated the lesions with Q-switched ruby laser.- - - - - - - - - - ranking = 1keywords = ochronosis (Clic here for more details about this article) |
8/84. Alkaptonuric ochronosis presenting as palmoplantar pigmentation.We describe a 37-year-old woman who presented with palmoplantar pigmentation, thickening and pitting of 4 years duration. Bluish pigmented patches were seen over the sclera of her eyes. Her lumbar spine showed typical calcification of the intervertebral discs. Addition of Benedict's reagent to a urine sample of the patient gave rise to greenish brown precipitate and brownish black supernatant. Alkalinization of urine turned it black. A biopsy of the palmar lesion demonstrated irregular breaking up, swelling and homogenization of collagen bundles in the reticular dermis. Yellow-brown (ochre coloured) pigment was seen lying within the collagen bundles and also freely in the deeper dermis confirming our clinical diagnosis of alkaptonuric ochronosis. To the best of our knowledge this is probably the second report of alkaptonuria presenting with palmoplantar pigmentation.- - - - - - - - - - ranking = 1keywords = ochronosis (Clic here for more details about this article) |
9/84. A case of ochronosis: MRI of the lumbar spine.We present the MRI features of the lumbar spine in a patient with ochronosis.- - - - - - - - - - ranking = 1keywords = ochronosis (Clic here for more details about this article) |
10/84. dura mater involvement in ochronosis (alkaptonuria).Clinical manifestations of alkaptonuria have been well described and are most commonly characterized by ochronosis or pigmentation of connective tissue. Sites most commonly involved in ochronosis include joints, heart, skin, and kidney. We describe a 66-year-old woman with a history of alkaptonuria who had widespread ochronosis. The dura mater showed extensive pigment deposition, which was evident both grossly and microscopically at autopsy. To our knowledge, description of dura mater involvement by ochronosis has not been previously reported in the literature.- - - - - - - - - - ranking = 1.6keywords = ochronosis (Clic here for more details about this article) |
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