[SOME DATA ON THE CLINICAL PICTURE OF ALKAPTONURIA. MODIFIED METHOD FOR THE DETERMINATION OF ALKAPTONURIA AND HOMOGENTISIC ACID].
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Alkaptonuria↗
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Alkaptonuria with lumbar disc herniation: a report of two cases.
STUDY DESIGN: Two cases of lumbar disc herniation with alkaptonuria are presented. OBJECTIVES: To present a probable clinical course of lumbar disc herniation with alkaptonuria, a rare metabolic disease. SUMMARY OF BACKGROUND DATA: Although lumbar disc disease is a common clinical occurrence in alkaptonuria, lumbar disc surgery is needed rarely in this disease. A patient with alkaptonuria without ochronotic signs is also rarely seen. METHODS: The cause, clinical presentation, diagnostic techniques and treatment of alkaptonuria with lumbar disc disease are reviewed. RESULTS: The symptoms of the patients disappeared after surgery, and there were no symptoms on follow-up. CONCLUSION: Alkaptonuria frequently occurs in association with lumbar disc disease. In patients with no other signs of alkaptonuria or ochronosis, early detection of the disease is important to treat involvement of other systems (e.g., cardiovascular and urinary).
Adult↗
Homozygosity mapping of the gene for alkaptonuria to chromosome 3q2.
Alkaptonuria, the first human disorder recognized by Garrod as an inborn error of metabolism, is a rare recessive condition that darkens urine and causes a debilitating arthritis termed ochronosis. We have studied two families with consanguineous parents and four affected children in order to map the gene responsible for alkaptonuria. Coinheritance of either neonatal severe hyperparathyroidism or sucrase-isomaltase deficiency and alkaptonuria provided a candidate location for the mutated genes on chromosome 3. Homozygosity mapping with polymorphic loci identified a 16 centiMorgan region on chromosome 3q2 that contains the alkaptonuria gene. Analysis of two additional nonconsanguineous families supports linkage of alkaptonuria to this single locus (combined lod score = 4.3, theta = 0).
Adult↗
A novel therapeutic trial of homogentisic aciduria in a murine model of alkaptonuria.
Alkaptonuria is a rare autosomal recessive disorder characterized by homogentisic aciduria, ochronosis, and arthritis. Although a deficiency of homogentisic acid 1,2-dioxygenase has recently been confirmed at the molecular level, no effective treatment regimen has yet been developed for this disorder. In the present study, 2(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), a potent inhibitor of p-hydroxyphenylpyruvate dioxygenase (which catalyzes the formation of homogentisic acid from p-hydroxyphenylpyruvic acid) was adopted as a possible therapeutic agent for alkaptonuria. NTBC dose-dependently reduced the urinary output of homogentisic acid in a murine model of alkaptonuria that had been created with ethylnitrosourea. These findings suggest that NTBC may be the first potent pharmacotherapeutic agent for alkaptonuria.
4-Hydroxyphenylpyruvate Dioxygenase↗
Natural history of alkaptonuria.
BACKGROUND: Alkaptonuria, caused by mutations in the HGO gene and a deficiency of homogentisate 1,2-dioxygenase, results in an accumulation of homogentisic acid (HGA), ochronosis, and destruction of connective tissue. There is no effective therapy for this disorder, although nitisinone inhibits the enzyme that produces HGA. We performed a study to delineate the natural history of alkaptonuria. METHODS: We evaluated 58 patients with alkaptonuria (age range, 4 to 80 years), using clinical, radiographic, biochemical, and molecular methods. A radiographic scoring system was devised to assess the severity of spinal and joint damage. Two patients were treated with nitisinone for 10 and 9 days, respectively. RESULTS: Life-table analyses showed that joint replacement was performed at a mean age of 55 years and that renal stones developed at 64 years, cardiac-valve involvement at 54 years, and coronary-artery calcification at 59 years. Linear regression analysis indicated that the radiographic score for the severity of disease began increasing after the age of 30 years, with a more rapid increase in men than in women. Twenty-three new HGO mutations were identified. In a 51-year-old woman, urinary HGA excretion fell from 2.9 to 0.13 g per day after a 10-day course of nitisinone (7 days at a dose of 0.7 mg per day and 3 days at 2.8 mg per day). In a 59-year-old woman, urinary HGA fell from 6.4 g to 1.7 g per day after nine days of treatment with nitisinone (0.7 mg per day). Plasma tyrosine levels in these patients rose from approximately 1.1 mg per deciliter (60 micromol per liter) in both to approximately 12.8 mg per deciliter (700 micromol per liter) and 23.6 mg per deciliter (1300 micromol per liter), respectively, with no clinical signs or symptoms. CONCLUSIONS: The reported data on the natural history of alkaptonuria provide a basis for the evaluation of long-term therapies. Although nitisinone can reduce HGA production in humans with homogentisate 1,2-dioxygenase deficiency, the long-term safety and efficacy of this treatment require further evaluation.
4-Hydroxyphenylpyruvate Dioxygenase↗
[HLA-B27 antigen and alkaptonuria].
Study of urinary homogentisic acid and a determinantion of group HLA were carried out for 36 members of a family spread over three generations with three cases of ochronotic rheumatism in the second generation. Alkaptonuria was discovered in seven other subjects, six of them members of the third generation: urinary elimination was poor, less than 0.60 g/24 hours. There is a certain degree of consanguinity in the family studied here and these findings do not therefore rule out a recessive autosomal transmission of the alkaptonuria. They do however lead to the consideration that alkaptonuria may sometimes be found in heterozygotic subjects. A genetic relationship between HLA complex and alkaptonuria can only be claimed with difficulty from this familial study, but the high frequency of B 27 antigen (29 out of 36 members carring it) leaves room for the hypothesis that the B 27 gene, or more precisely a gene associated with the B 27 gene, plays a part in the development of ochronotic rheumatism.
Adult↗
The human gene for alkaptonuria (AKU) maps to chromosome 3q.
Alkaptonuria (AKU; McKusick no. 203500) is a rare autosomal recessive disorder caused by the lack of homogentisic acid oxidase activity. Patients excrete large amounts of homogentisic acid in their urine and a black ochronotic pigment is deposited in their cartilage and collagenous tissues. Ochronosis is the predominant clinical complication of the disease leading to ochronotic arthropathy, dark urine, pigment changes of the skin, and other clinical features. A mutation causing alkaptonuria in the mouse has mapped to chromosome 16. Considering conserved synteny, we were able to map the human gene to chromosome 3q in six alkaptonuria pedigrees of Slovak origin.
Alkaptonuria↗
Alkaptonuria and ochronosis: case report and review.
Alkaptonuria is a rare genetic disorder in which the enzyme homogentisic acid oxidase is deficient, resulting in the accumulation of homogentisic acid in various bodily tissues. This is a multisystem disorder with a characteristic blue-black discoloration of the skin and cartilage, which is termed ochronosis. Herein we report a profound case of ochronosis secondary to alkaptonuria. Furthermore, we review the clinical manifestations of alkaptonuria and discuss the spectrum of ochronosis, both endogenous and exogenous.
Aged↗
Exacerbation of the ochronosis of alkaptonuria due to renal insufficiency and improvement after renal transplantation.
In alkaptonuria, homogentisate 1,2-dioxygenase deficiency causes tissue accumulation of homogentisic acid (HGA), followed by signs and symptoms of ochronosis. These include massive urinary excretion of HGA, arthritis and joint destruction, pigmentation of cartilage and connective tissue, and cardiac valve deterioration. We describe a 46-year-old man with alkaptonuria and diabetic renal failure whose plasma HGA concentration was twice that of any other alkaptonuria patient, and whose ochronosis progressed much more rapidly than that of his two alkaptonuric siblings. After renal transplantation, the plasma HGA normalized, and the daily urinary excretion of HGA decreased by 2-3g. This case illustrates the critical role of renal tubular secretion in eliminating HGA from the body, and suggests that renal transplantation in a uremic patient not only restores HGA excretion, but may also provide homogentisate 1,2-dioxygenase activity for the metabolism of HGA.
Adult↗
Allelic heterogeneity of alkaptonuria in Central Europe.
Defects of the homogentisate 1,2 dioxygenase (HGO; E.C. No. 1.13.11.5) have been identified as the molecular cause of alkaptonuria in humans (AKU) and the aku mouse. Here, we report on the genetic basis of 30 AKU patients from Central Europe. In addition to five mutations described previously, we have detected five novel HGO mutations. Recombinant expression of mutated HGO enzymes in E. coli demonstrates the inactivating effect of three of these mutations. A genetic epidemiologic study in Slovakia, the country with the highest incidence of alkaptonuria, demonstrates that two recurrent mutations (c.183-1G > A and Glyl61Arg) are found on more than 50% of AKU chromosomes. An analysis of the allelic association with intragenic DNA markers and of the geographic origins of the AKU chromosomes suggests that several independent founders have contributed to the gene pool, and that subsequent genetic isolation is likely to be responsible for the high prevalence of alkaptonuria in Slovakia.
Alkaptonuria↗
Characterization of the pigment from homogentisic acid and urine and tissue from an alkaptonuria patient.
When urine samples from alkaptonuria patients are allowed to stand, they turn black, presumably owing to the oxidation of homogentisic acid to a melanin-like substance. We report the characterization of the pigments formed by polymerization of (a) the components in the urine from a patient with alkaptonuria and (b) homogentisic acid. The absorption spectra and electron spin resonance signals of these pigments are similar to those of eumelanins. Irradiation of the pigments with nitroblue tetrazolium caused reduction of the tetrazolium; this was partially inhibited by superoxide dismutase. Irradiation of Ehrlich ascites carcinoma cells with the pigments from homogentisic acid or urine caused cell lysis. Since this lysis was inhibited by catalase, we have concluded that it was mediated by H2O2. A similar pigment was also extracted from the tissue from an alkaptonuria patient. It is suggested that the degeneration of tissue in vivo may be due to the deposition of melanin-like pigments in the tissues, probably in combination with metal ions.
Alkaptonuria↗
Reversal of clinical symptoms and radiographic abnormalities with protein restriction and ascorbic acid in alkaptonuria.
There is no definitive treatment protocol for alkaptonuria. A patient with alkaptonuria was treated with ascorbic acid (0.5 g/day) from the age of 4 years. He developed episodes of severe recurrent joint pain at 9.5 years of age after which a protein-restricted diet (1.3 g/kg/day) was started. Protein restriction in combination with ascorbic acid therapy (1 g/day in two divided doses) resulted in a significant decrease but not a normalization of the urinary homogentisic acid excretion. Joint pain resolved and the radiological evidence of 'moth-eaten' irregularities on the articular surface in both knees disappeared. He is currently well, growing normally and in nitrogen balance. Our findings document a reversal of bone abnormalities and clinical symptoms in a case of alkaptonuria. The results should be confirmed in a larger study. We suggest that protein restriction should be applied in combination with ascorbic acid in affected patients as soon as joint pain occurs.
Alkaptonuria↗
Alkaptonuria and lumbar disc herniation. Report of three cases.
Alkaptonuria is a rare metabolic disease caused by deficiency of homogentisic acid oxidase and characterized by bluish-black discoloration of cartilages and skin (ochronosis). The authors report the cases of three patients with lumbar disc herniation who underwent discectomy and in whom the nucleus pulposus was discovered to be black. Alkaptonuria was diagnosed after discectomy. Discal herniation requiring surgery is unusual in alkaptonuria, with only a few reports. The symptoms in the three patients disappeared after surgery and no symptoms were demonstrated on follow-up examination.
Adult↗
Alkaptonuria caused by compound heterozygote mutations.
Alkaptonuria is a rare autosomal recessive disorder of inborn errors of metabolism. It is characterised by the deposition of "ochronotic pigment" especially in connective tissue as a result of deficieny of the "homogentisic acid oxidase" enzyme which has a role in the catabolism of tyrosine and phenylalanine. A compound heterozygote alkaptonuria patient, with manifestations in adulthood, without infantile and childhood signs is presented. The described alkaptonuria mutations are reported for the first time in the Turkish population.
Adult↗
[Alkaptonuria: a rare metabolic disorder. A report of two cases in siblings].
Alkaptonuria is a rare metabolic condition caused by congenital homogentisate oxidase deficiency of recessive inheritance. Homogentisate polymers are accumulated and cause urine darkening, brown pigmentation of connective tissue, articular cartilage pathology. The authors present clinical picture, pathogenesis, diagnostic and therapeutic possibilities in patients with alkaptonuria. Two siblings with alkaptonuria are described.
Alkaptonuria↗
[Ochronotic arthropathy in alkaptonuria. Radiological manifestations and physiopathological signs].
Alkaptonuria is a rare autosomal recessive metabolic disease, due to the lack of homogentisic acid oxidase. The following accumulation of homogentisic acid brings about a black discoloration of both the urine (alkaptonuria) and connective tissue (ochronosis). The ochronotic alterations into joint cartilages cause degenerative arthropathy and osteopenia. The radiological features of three unrelated cases of alkaptonuria are reported. Radiographic abnormalities of ochronotic arthropathy are found in both the spine and the extraspinal joints. In the spine, the progressive calcification and "vacuum" phenomenon of disc spaces are the most characteristic findings. Disc space narrowing is associated with calcification and marginal sclerosis of vertebral bodies and is accentuated by osteopenia. Osteophytes are usually absent or of small size; nevertheless progressive formation of marginal intervertebral bridges and obliteration of disc spaces at multiple levels ("pseudoblock vertebrae") may occur. In extraspinal sites, space narrowing, bone sclerosis and fragmentation may also be observed. Diagnosis of ochronotic arthropathy is often suggested by radiographs of the spine, and it is confirmed afterwards by clinical and laboratory findings. The characteristic radiological findings of ochronotic spondylitis, in the final stage, include narrowing of at least four lumbar disc spaces, associated with their calcification and "vacuum" phenomenon, "pseudoblock vertebrae", marginal sclerosis and osteopenia of vertebral bodies.
Aged↗
Alkaptonuria.
Alkaptonuria is found relatively frequently in Slovakia, Eastern Czechoslovakia (1 in 25,000 inhabitants). Reported herein are the clinical, radiographic, and biochemical aspects and genetics of 126 patients with alkaptonuria. Forty-seven were diagnosed in childhood; the sequential appearance of each manifestation is documented by decade. A simple screening method for this disorder is described. Pedigree analyses confirm recessive inheritance. Possible genetic and sociologic factors responsible for this high frequency of alkaptonuria are discussed.
Adolescent↗
[Clinical aspects of alkaptonuria].
The research laboratory of clinical genetics in Martin has initiated an extensive study on alkaptonuria since 1968. The incidence of that disease among the newborn in Slovakia is 1:21,500 and 140 patients have so far been recorded (136 in Slovakia and 13 from Moravia frontier regions). Though the incidence and clinical manifestation of alkaptonuria differ in the separate cases, the progress of the disease is associated with the age of the patient. Of particular significance for the clinical diagnosis of alkaptonuria is not only the knowledge of the clinical manifestations in general but also the clinical picture among the various age groups. Our experiment is presented in the paper from that point of view.
Adolescent↗