5C50.10

ICD-11 MMS 2026-01

Alkaptonuria

Description

Alkaptonuria is characterised by the accumulation of homogentisic acid (HGA) and its oxidised product benzoquinone acetic acid (BQA), leading to a darkening of the urine when it is left exposed to air, grey-blue colouration of the eye sclerae and the ear helix (ochronosis), and a disabling joint disease involving both the axial and peripheral joints (ochronotic arthropathy).

Index terms

  • Alkaptonuria
  • Homogentisate 1,2-dioxygenase deficiency
  • Homogentisic acid oxidase deficiency
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  • Ochronosis
  • alcaptonuria
  • deficiency of homogentisate oxygenase
  • deficiency of homogentisicase
  • homogentisicaciduria
  • Endogenous ochronosis
  • Ochronotic arthritis

Exclusions from above levels

  • http://id.who.int/icd/entity/1191191920 – Disorders of lipoprotein metabolism or certain specified lipidaemias
  • 3A10.Z – Hereditary haemolytic anaemia due to enzyme deficiency
  • 5A71.01 – Congenital adrenal hyperplasia
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  • 5A81.1 – 5-alpha-reductase deficiency
  • LD28.01 – Marfan syndrome
  • LD28.1 – Ehlers-Danlos syndrome
  • LD2A.4 – androgen resistance syndrome
  • 18 – Pregnancy, childbirth or the puerperium
  • http://id.who.int/icd/entity/1004987305 – Transitory endocrine or metabolic disorders specific to fetus or newborn

Sibling codes

  • 5C50.11 – Tyrosinaemia type 1
  • 5C50.12 – Tyrosinaemia type 2
  • 5C50.1Y – Other specified disorders of tyrosine metabolism
  • 5C50.1Z – Disorders of tyrosine metabolism, unspecified

Foundation entity

Alkaptonuria – http://id.who.int/icd/entity/1761652827

Part of: 5C50.1: Disorders of tyrosine metabolism › 5C50: Inborn errors of amino acid or other organic acid metabolism › 05: Endocrine, nutritional or metabolic diseases