alkaptonuria

Altered activity of specific enzymes in phenylalanine-tyrosine (phe-tyr) metabolism results in incomplete breakdown of various metabolite substrates in this pathway. Increased biofluid concentration and tissue accumulation of the phe-tyr pathway metabolite homogentisic acid (HGA) is central to pathophysiology in the inherited disorder alkaptonuria (AKU). Accumulation of metabolites upstream of HGA, including tyrosine, occurs in patients on nitisinone, a licenced drug for AKU and hereditary tyrosinaemia type 1, which inhibits the enzyme responsible for HGA production...

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Alkaptonuria is a rare inborn error of metabolism caused by the deficiency of homogentisate 1,2-dioxygenase activity. The consequent homogentisic acid (HGA) accumulation in body fluids and tissues leads to a multisystemic and highly debilitating disease whose main features are dark urine, ochronosis (HGA-derived pigment in collagen-rich connective tissues), and a painful and severe form of osteoarthropathy. Other clinical manifestations are extremely variable and include kidney and prostate stones, aortic stenosis, bone fractures, and tendon, ligament and/or muscle ruptures...

INTRODUCTION: Alkaptonuria is a rare autosomal recessive disorder caused by the defective metabolism of homogentisic acid, with a rare course and remained undetected even until adulthood. Ochronotic arthropathy is one of the manifestations of alkaptonuria, predominantly affecting weight bearing joints such as spine, hip, and knee. Total joint arthroplasty is treatment of choice in end-stage arthritis of hip and knee. Owing to the rarity of the disease, limited data is available in literature regarding surgical challenges and long-term functional outcomes...

BACKGROUND: Alkaptonuria is a rare metabolic disease that causes an increase in homogentisic acid (HGA) due to a lack of enzymatic activity. Commonly, accumulation of HGA presents with dark discoloration of skin and other tissues, also known as ochronosis. Additionally, alkaptonuria can result in other clinical manifestations, including arthritis and cardiac disease. This case highlights alkaptonuria-related cardiac disease and challenges that cardiac surgery teams may face when treating this patient population...

INTRODUCTION: Alkaptonuria (AKU) is a rare autosomal-recessive multisystemic disease. It is caused by a mutant homogentisate dioxygenase coding gene, leading to the accumulation of homogentisic acid (HGA), hence systemic manifestations. Renal manifestations and tendon rupture are rarely reported. CASE REPORT: We report a 60-year-old male with chronic kidney disease for over a decade who was initially misdiagnosed with ankylosing spondylitis and rheumatoid arthritis...

Alkaptonuria is a rare genetic disorder characterized by the excessive production of homogentisic acid, leading to the formation and deposition of pigment polymers throughout the body. It is extremely rare, affecting only around one in 100,000 individuals. Despite the normal life expectancy, it can cause severe morbidities. Alkaptonuria is typically managed supportively with pain medication, dietary modifications, and surgical interventions, which are considered to be the gold standard of therapy. Here we present a case of a 33-year-old male with no previous medical or surgical history who presented with severe acute back pain radiating to the left leg...

Endogenous ochronosis, also known as alkaptonuria, is a rare disease known for its bluish-black discoloration of the skin, sclerae, and pinnae, as well as urine that turns black upon standing. Though rarely fatal, joint degradation is a common sequela, and many patients require multiple large joint arthroplasties throughout their lifetime. Though many aspects of the pathophysiological mechanisms of the disease have been described, questions remain, such as how the initiation of ochronotic pigmentation is prompted and the specific circumstances that make some tissues more resistant to pigmentation-related damage than others...

No abstract text is available yet for this article.

Alkaptonuria is a very rare disorder in which homogentisic acid accumulates due to a deficiency in the activity of homogentisic acid 1,2 dioxygenase. This deficiency results in deposition of a yellowish-brown pigment in connective tissue. Such deposition is termed 'ochronosis' and leads to deterioration in the formation and structure of proteoglycans in hyaline cartilage. These actions lead to fragmentation and rapid destructive arthritis. Often, ochronotic arthritis appears at 40-60 years of age, and many patients are treated symptomatically...

OBJECTIVE: Homogentisic acid (HGA) is excreted in excessive amounts in the urine of patients with alkaptonuria, which is a hereditary metabolic disorder of phenylalanine and tyrosine. Therefore, the detection of HGA in urine is useful for the diagnosis of alkaptonuria. To evaluate the detection of HGA, we confirmed the color shift of HGA solutions and analyzed them by electrospray ionization mass spectrometry (ESI-MS). METHODS: We observed the color change of the HGA solutions under different pH conditions (pH 6...

Ochronosis is a rare autosomal recessive disorder of tyrosine metabolism characterized by multilevel spinal degeneration and arthritis of large weight-bearing joints, which is referred to as ochronotic arthropathy. In this case report, we describe diagnosis and treatment of ochronotic arthropathy in a patient who underwent total hip arthroplasty (THA) and total knee arthroplasty (TKA). The Harris hip score was 26 preoperatively and 45, 68, 76, 90, 92, and 94 at 1, 3, 6, 9, 11, and 14 months, respectively, postoperatively...

Alkaptonuria is a rare autosomal recessive trait. Symptomatic lumbar disc herniation warranting surgical intervention is a rare scenario in alkaptonuria and only a few cases have been described in the literature. We present one such rare case of alkaptonuria in a 31-year-old female presenting with low back pain and left leg radiculopathy not relieved with conservative management. Roentgenograms of the lumbar spine revealed wafer-like disc calcifications and MRI showed a herniated disc at the L4-L5 level with deeply hypointense disc spaces in T2 suggestive of disc calcification and associated modic type 2 changes...

Alkaptonuria is an extremely rare autosomal recessive metabolic disorder characterized by dark urine, ochronosis, and arthritis of the spine and major joints. We report a case of ochronotic arthritis observed during total knee replacement surgery in a 65-year-old male patient with no relevant medical history. Based on a literature review, this is the first case of ochronotic arthritis reported in Korea.

Alkaptonuria (AKU) is a rare autosomal recessive metabolic disorder caused by pathogenic variants in the homogentisate 1,2-dioxygenase (HGD) gene. This leads to a deficient HGD enzyme with the consequent accumulation of homogentisic acid (HGA) in different tissues causing complications in various organs, particularly in joints, heart valves and kidneys. The genetic basis of AKU in Egypt is completely unknown. We evaluated the clinical and genetic spectrum of six pediatric and adolescents AKU patients from four unrelated Egyptian families...

Inborn metabolic diseases (IMD) are rare conditions that can be diagnosed during adulthood. Patients with IMD may have joint symptoms and the challenge is to establish an early diagnosis in order to institute appropriate treatment and prevent irreversible damage. This review describes the joint manifestations of IMD that may be encountered in adults. The clinical settings considered were arthralgia and joint stiffness as well as arthritis. Unspecific arthralgias are often the first symptoms of hereditary hemochromatosis, chronic low back pain may reveal an intervertebral disc calcification in relation with alkaptonuria, and progressive joint stiffness may correspond to a mucopolysaccharidosis or mucolipidosis...

Ankylosing spondylitis is the most common type of seronegative inflammatory spondyloarthropathy often presenting with low back or neck pain, stiffness, kyphosis and fractures that are initially missed on presentation; however, there are other spondyloarthropathies that may present similarly making it a challenge to establish the correct diagnosis. Here, we will highlight the similarities and unique features of the epidemiology, pathophysiology, presentation, radiographic findings, and management of seronegative inflammatory and metabolic spondyloarthropathies as they affect the axial skeleton and mimic ankylosing spondylitis...

Alkaptonuria is a rare metabolic disorder characterized by the accumulation of homogentisic acid. Its effects on the central nervous system are well-recognized; however, cases of pathologic homogentisic acid deposition in the peripheral nervous system are less well-described. We report the case of a 72-year-old man with a prior history of alkaptonuria presenting with bilateral carpal tunnel and left-sided cubital tunnel symptoms. This case is of note because the patient demonstrated a rapid onset of symptoms due to pathology at multiple foci...

Nitisinone has been approved for treatment of alkaptonuria (AKU). Non-invasive biomarkers of joint tissue remodelling could aid in understanding the molecular changes in AKU pathogenesis and how these can be affected by treatment. Serological and urinary biomarkers of type I collagen and II collagen in AKU were investigated in patients enrolled in the randomized SONIA 2 (NCT01916382) clinical study at baseline and yearly until the end of the study (Year 4). The trajectories of the biomarkers over time were observed...

Despite urgent warnings about the spread of multidrug-resistant bacteria, the antibiotic development pipeline has remained sparsely populated. Naturally occurring antibacterial compounds may provide novel chemical starting points for antibiotic development programs and should be actively sought out. Evaluation of homogentisic acid (HGA), an intermediate in the tyrosine degradation pathway, showed that the compound had innate activity against Gram-positive and Gram-negative bacteria, which was lost following conversion into the degradation product benzoquinone acetic acid (BQA)...