1,054 results match your criteria Ochronosis

Long-term follow-up of alkaptonuria patients: single center experience.

J Pediatr Endocrinol Metab 2022 Jun 6. Epub 2022 Jun 6.

Department of Pediatrics, Ege University Faculty of Medicine, Division of Pediatric Metabolism, Izmir, Turkey.

Objectives: Alkaptonuria is a rare autosomal recessive genetic disorder resulting from the deficiency of homogentisate 1,2 dioxygenase (HGD), the third enzyme in the tyrosine degradation pathway. Homogentisic acid produced in excess oxidizes into ochronotic pigment polymer. Accumulation of this pigment in various tissues leads to systemic disease. Read More

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Total Knee Replacement in Alkaptonuric Ochronosis.

Acta Biomed 2022 Jun 7;93(S1):e2022108. Epub 2022 Jun 7.

Department of Orthopaedic and Traumatology, Hospital Británico de Buenos Aires.

Background And Objective: Alkaptonuria is a rare disease characterized by the accumulation of homogentisic acid (HGA). Over time, these patients may develop disabling ochronotic arthropathy. We present 2 cases of patients with end-stage arthropathy treated with total knee arthroplasty (TKA). Read More

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[Ochronosis: A case report].

Rev Med Interne 2022 Jun 2. Epub 2022 Jun 2.

Département de rhumatologie, CHU Ibn-Rochd, Casablanca, Maroc.

Introduction: Ochronosis, also known as alkaptonuria, is a rare autosomal recessive disease. It is caused by a lack of homogentisic acid oxidase, which causes homogentisic acid deposition in the tissues.

Case Report: We report a 69-year-old patient who presented with chronic mechanical low back and radicular pain. Read More

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Disc calcifications: Think of ochronosis.

Daniel Wendling

Joint Bone Spine 2022 Apr 30;89(6):105395. Epub 2022 Apr 30.

Rhumatologie, CHU de Besançon et Université de Franche-Comté, Besançon, France. Electronic address:

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Incidental diagnosis of ochronosis by aortic valve replacement.

Turk Gogus Kalp Damar Cerrahisi Derg 2022 Jan 28;30(1):117-120. Epub 2022 Jan 28.

Department of Cardiovascular Surgery, Adana City Training and Research Hospital, Adana, Turkey.

Alkaptonuria is a rare inherited metabolic disease caused by homogentisic acid oxidase enzyme deficiency. Homogentisic acid formed during phenylalanine and tyrosine metabolism cannot be further metabolized and accumulates due to this enzyme deficiency. Some of the homogentisic acid that cannot be removed by metabolism is excreted with urine, some of it causes this accumulation known as ochronosis, which is characterized by dark pigmented color change in tissues. Read More

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January 2022

Blue man: Ochronosis in Otolaryngology.

Clin Case Rep 2022 Apr 15;10(4):e05717. Epub 2022 Apr 15.

West Cancer Center Germantown Tennessee USA.

Blue discoloration of the skin and cartilage, or ochronosis, is a rare physical examination finding. We present two cases of childhood onset ochronosis, one exogenous and one endogenous in etiology. The first was caused by minocycline use for severe acne, and the second was caused by congenital alkaptonuria. Read More

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Clinical and Surgical Insights on Bilateral Total Knee Arthroplasty in Ochronotic Arthropathy: A Case-based Review.

J Orthop Case Rep 2021 Dec;11(12):30-34

Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.

Introduction: Ochronotic arthropathy (OcA) is a consequence of alkaptonuria, a rare systemic-inherited metabolic disorder leading to accumulation of homogentisic acid in articular cartilage and subsequent early degeneration of the joints. Only few cases of OcA managed with bilateral total knee arthroplasty (TKA) has been described in the literature so far. We aim to discuss surgical pearls, pitfalls, and clinical outcome of OcA of knees managed with simultaneous bilateral TKA. Read More

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December 2021

Ochronotic Surprise during Total Knee Replacement! A Case Report.

J Orthop Case Rep 2021 Oct;11(10):49-52

Department of Orthopedics, Lourdes Hospital, Kochi, Kerala, India.

Introduction: Alkaptonuria is a rare autosomal recessive metabolic disorder characterized by accumulation of homogentisic acid (HGA) due to an inherited deficiency of the enzyme HGA oxidase. Unlike rheumatoid arthritis which affects the small joints of the hands and feet, ochronotic arthropathy predominantly involves the large weight-bearing joints such as hips, knees, and spine. The knee is the most common joint to be affected. Read More

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October 2021


Port J Card Thorac Vasc Surg 2022 Jan 4;28(4):47-49. Epub 2022 Jan 4.

Serviço de Anestesiologia, Centro Hospitalar de Vila Nova de Gaia/Espinho, Portugal.

Introduction: Near infrared spectroscopy is a non-invasive method to assess regional oxygenation and is being used in transcatheter aortic valve implantation to document periods of cerebral hypoperfusion, where cerebrovascular events are one of the most feared complications. Alkaptonuria is a rare metabolic disease characterized by accumulation of homogentisic acid in tissues and body fluids. The accumulation of pigment might interfere with the absorption of near infrared light, used in near infrared spectroscopy monitoring. Read More

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January 2022

Basophilic, Thickened Collagen Bundles Seen in Late-Stage Exogenous Ochronosis.

Am J Dermatopathol 2022 07 4;44(7):508-509. Epub 2022 May 4.

St. Luke's University Health System, St. Luke's/Temple School of Medicine, Bethlehem, PA.

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Sarcoidal granuloma on exogenous ochronosis.

Ann Dermatol Venereol 2022 Feb 17. Epub 2022 Feb 17.

Department of Dermatology, Hospital Institute of Social Hygiene (IHS), Dakar, Cheikh Anta Diop University, Dakar, Senegal.

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February 2022

Disorders of Hyperpigmentation. Part I. Pathogenesis and clinical features of common pigmentary disorders.

J Am Acad Dermatol 2022 Feb 10. Epub 2022 Feb 10.

Department of Dermatology, Henry Ford Hospital, Detroit, MI, USA. Electronic address:

Disorders of hyperpigmentation are common, and depending on the extent and location of involvement, can affect quality of life and pose a significant psychological burden for patients. Given the similarities in presentation of various causes of hyperpigmentation, it is often difficult to elucidate the etiology of these conditions, which is important to guide management. Furthermore, certain disorders such as lichen planus pigmentosus and ashy dermatosis have similar clinical and/or histologic presentations, and their classification as distinct entities has been debated, leading to additional confusion. Read More

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February 2022

Neglected alkaptonuric patient presented with low back pain and radiculopathy: A case report.

Surg Neurol Int 2022 12;13:15. Epub 2022 Jan 12.

Department of Neurosurgery, Razavi Hospital, Mashhad, Iran.

Background: Alkaptonuria (AKU) is a rare hereditary disorder in which excess homogentisic acid (HGA) deposits in connective tissues (ochronosis). Here, we report the unusual presentation of a lumbar disc herniation occurring in a patient with AKU warranting surgical intervention.

Case Description: A 28-year-old male presented with 1 year of low back pain. Read More

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January 2022

Homogentisic acid induces autophagy alterations leading to chondroptosis in human chondrocytes: Implications in Alkaptonuria.

Arch Biochem Biophys 2022 03 25;717:109137. Epub 2022 Jan 25.

Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100, Siena, Italy. Electronic address:

Alkaptonuria (AKU) is an ultra-rare genetic disease caused by a deficient activity of the enzyme homogentisate 1,2-dioxygenase (HGD) leading to the accumulation of homogentisic acid (HGA) on connective tissues. Even though AKU is a multi-systemic disease, osteoarticular cartilage is the most affected system and the most damaged tissue by the disease. In chondrocytes, HGA causes oxidative stress dysfunctions, which induce a series of not fully characterized cellular responses. Read More

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Hyperpigmentation: Looking beyond hydroquinone.

J Cosmet Dermatol 2022 Jan 12. Epub 2022 Jan 12.

Succor Pharma Solutions, Dubai Science Park, Dubai, United Arab Emirates.

Hyperpigmentation is the most common complaint in the age group 40-45 years, seeking consultation for skin disorders. Hydroquinone is a commonly used depigmenting agent in clinical practice for treating hyperpigmentation. Prolonged use of hydroquinone has been associated with cancer risk and exogenous ochronosis. Read More

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January 2022

Blue-black hyperpigmented patches on the cheeks.

JAAD Case Rep 2022 Jan 17;19:81-83. Epub 2021 Nov 17.

Department of Dermatology, Georgetown University MedStar Washington Hospital Center, Washington, DC.

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January 2022

Alkaptonuria with rapidly destructive arthropathy of the hip: A case report and literature review.

Acta Orthop Traumatol Turc 2021 Dec;55(6):563-568

Department of Orthopedic Surgery, Oita University, School of Medicine, Yufu City, Oita 879-5593, Japan.

Alkaptonuria-related rapidly destructive arthropathy of the hip joint has not been reported in detail with both imaging and histopathological findings in the literature. We, herein, presented the case of a 79-year-old male patient who suddenly started experiencing marked right hip pain. Radiography showed that the femoral head was spherical; however, after 3 months, approximately half of the femoral head was destroyed despite there being almost no change in the acetabulum. Read More

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December 2021

Musculoskeletal manifestations in Alkaptonuria: A cross-sectional study.

Medicine (Baltimore) 2021 Dec;100(51):e28241

Department of Pathology& Laboratory Medicine, Faculty of Pathology, Aga Khan University, Karachi, Pakistan.

Abstract: This study aimed to determine the patient characteristics and clinical presentation of Alkaptonuria cases reported by the Biochemical Genetics Lab.An observational study was conducted at the Biochemical Genetics Lab. Alkaptonuria patients were diagnosed based on the homogentisic acid peak in urine and their demographics and clinical data collected from to 2013 to 2019. Read More

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December 2021

Treatment of osteoporotic fractures in alkaptonuria by teriparatide stimulates bone formation and decreases fracture rate - A report of two cases.

Bone Rep 2021 Dec 28;15:101151. Epub 2021 Nov 28.

IACD, University of Liverpool, William Henry Duncan Building, West Derby Street, Liverpool L7 8TX, United Kingdom.

Two cases of advanced alkaptonuria (AKU) with co-existing osteoporosis are described. Case 1 developed multiple non-vertebral fragility fractures, while Case 2 developed vertebral fragility fractures, both refractory to bisphosphonates. Difficulties in diagnosing osteoporosis in AKU complicated by extensive calcifying and ossifying spondylosis are discussed. Read More

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December 2021

Dogliotti and Phillips classifications are unsuitable for grading the histopathological findings of exogenous ochronosis.

J Cutan Pathol 2022 May 26;49(5):434-437. Epub 2021 Dec 26.

Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.

Background: Cutaneous exogenous ochronosis (EO) is frequently graded and staged according to the Dogliotti or Phillips classification system, both in research studies and in clinical practice. There are no data to support the use of these systems in either of these settings. These systems additionally purport that the clinical and histopathological findings of EO are concordant; however, anecdotal evidence suggests otherwise. Read More

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Alkaptonuria: clinical manifestations and an updated approach to treatment of a rare disease.

BMJ Case Rep 2021 Dec 7;14(12). Epub 2021 Dec 7.

Department of Upper GI Surgery, St.James Hospital, Dublin, Ireland.

Alkaptonuria (AKU) is a rare autosomal recessive disorder with a global incidence of 1 in 250 000 to 1 million people worldwide. It results from a deficiency of the enzyme homogentisic acid (HGA) oxidase which when absent, leads to an accumulation of HGA. Without this enzymatic degradation, HGA deposits in connective tissues resulting in pigmentation (ochronosis), plaque formation and accelerated cartilage destruction. Read More

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December 2021

A molecular spectroscopy approach for the investigation of early phase ochronotic pigment development in Alkaptonuria.

Sci Rep 2021 11 19;11(1):22562. Epub 2021 Nov 19.

Department of Biotechnology, Chemistry and Pharmacy, University of Siena, via Aldo Moro 2, Siena, Italy.

Alkaptonuria (AKU), a rare genetic disorder, is characterized by the accumulation of homogentisic acid (HGA) in organs due to a deficiency in functional levels of the enzyme homogentisate 1,2-dioxygenase (HGD), required for the breakdown of HGA, because of mutations in the HGD gene. Over time, HGA accumulation causes the formation of the ochronotic pigment, a dark deposit that leads to tissue degeneration and organ malfunction. Such behaviour can be observed also in vitro for HGA solutions or HGA-containing biofluids (e. Read More

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November 2021

The Black Knee - A Case Report.

J Orthop Case Rep 2021 Jul;11(7):94-97

Department of Orthopaedic, Orthopaedic Arthroscopy Knee and Shoulder Clinic, 707, Panchshil Plaza, Hughes Road, Mumbai - 400 007, Maharashtra, India.

Introduction: Ochronotic arthropathy in patients with alkaptonuria is a rare hereditary disorder. The altered metabolism causes the homogentesic acid derivatives to deposit in various connective tissues causing characteristic pigmentation. Due to the close clinical resemblance to that of a degenerative disorder, diagnosis of ochronotic arthropathy usually occurs intraoperatively. Read More

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Black Aorta from Alkaptonuria.

Aorta (Stamford) 2021 Aug 29;9(4):165-166. Epub 2021 Oct 29.

Department of Cardiothoracic Surgery, Wellington Regional Hospital, Wellington, New Zealand.

A-76-year old male with a past history of alkaptonuria with ochronosis (homogentisic acid deposition in tissues) had symptomatic aortic stenosis. Surgical replacement of the valve was undertaken, and he was noted to have a severely pigmented and porcelain aorta. Read More

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[Severe spine lesion following alkaptonuria. Case report].

Zh Vopr Neirokhir Im N N Burdenko 2021 ;85(5):104-109

Blokhin Russian Cancer Research Center, Moscow, Russia.

Alkaptonuria is a rare autosomal recessive disease. In these patients, melanin-like compounds as the final products of impaired metabolism of homogentisic acid are deposited mainly in connective tissue, including cartilage tissue of intervertebral discs. Similar to other degenerative spine diseases, lumbar segment is often damaged. Read More

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November 2021

A novel deep intronic variant strongly associates with Alkaptonuria.

NPJ Genom Med 2021 Oct 22;6(1):89. Epub 2021 Oct 22.

Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.

Alkaptonuria is a rare autosomal recessive inherited disorder of tyrosine metabolism, which causes ochronosis, arthropathy, cardiac valvular calcification, and urolithiasis. The epidemiology of alkaptonuria in East Asia is not clear. In this study, patients diagnosed with alkaptonuria from January 2010 to June 2020 were reviewed. Read More

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October 2021

Alkaptonuria in Russia.

Eur J Hum Genet 2022 02 10;30(2):237-242. Epub 2021 Sep 10.

Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.

Alkaptonuria is characterized by the accumulation of homogentisic acid (HGA), part of which is excreted in the urine but the excess HGA forms a dark brown ochronotic pigment that deposits in the connective tissue (ochronosis), eventually leading to early-onset severe arthropathy. We analyzed a cohort of 48 Russian AKU families by sequencing all 14 exons (including flanking intronic sequences) of the homogentisate 1,2-dioxygenase gene (HGD) and Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. Nine novel likely pathogenic HGD variants were identified, which have not been reported previously in any other country. Read More

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February 2022

Exogenous ochronosis associated with hydroquinone: a systematic review.

Int J Dermatol 2022 Jun 6;61(6):675-684. Epub 2021 Sep 6.

Department of Dermatology, Weill Cornell Medicine, New York, NY, USA.

Exogenous ochronosis is a potential side effect associated with hydroquinone, and treatment is often unsatisfactory. Our study objectives were to review data on hydroquinone-associated ochronosis to determine risk factors for patients experiencing this adverse event. On September 27, 2020 (MEDLINE/PubMed), and October 30, 2020 (Scopus and Web of Science), databases were searched for "ochronosis + hydroquinone" by both authors to reduce risk basis. Read More

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Bilateral Breast Ochronosis: a Case Report.

JPRAS Open 2021 Dec 18;30:23-28. Epub 2021 Jun 18.

Beaumont Hospital, Ireland.

Ochronosis is a syndrome characterized by bluish black discoloration due to the deposition of polymerized products of homogentisic acid (HGA) in the connective tissues. The endogenous variety (alkaptonuria), is a rare autosomal recessive metabolic disorder. The disorder is manifested by deficiency of the enzyme homogentisate 1,2-dioxygenase. Read More

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December 2021