Search for a rare disease

* (*) mandatory field

Other search option(s)

Suggest an update

(*) Required fields.


Only comments seeking to improve the quality and accuracy of information on the Orphanet website are accepted. For all other comments, please send your remarks via contact us. Only comments written in English can be processed.

Orphanet doesn't provide personalised answers. To get in touch with the Orphanet team, please contact

Information provided in your contribution (including your email address) will be stocked in .CSV files that will be sent as an email to Orphanet's teams. These emails might be conserved in the teams' mailboxes, in our backoffice servers but will not be registered in our databases (for more information see our section General Data Protection Regulation and data privacy (GDPR) and Confidentiality).

Captcha image

Class I glucose-6-phosphate dehydrogenase deficiency

Disease definition

A rare constitutional hemolytic anemia due to an enzyme disorder characterized by severe glucose-6-phosphate dehydrogenase deficiency (typically <10% residual enzyme activity) associated with chronic non-spherocytic hemolytic anemia of highly variable severity. Patients are at risk of developing neonatal jaundice (potentially leading to kernicterus), gallstones, and reticulocytosis and splenomegaly. They have an increased susceptibility to oxidizing agents provoking episodes of acute hemolysis. Favism, which describes the occurrence of an acute hemolytic reaction in response to the ingestion of fava beans, is more common in infants and young children.


Classification level: Disorder
  • Synonym(s):
    • Class I G6PD deficiency
    • Severe hemolytic anemia due to G6PD deficiency
  • Prevalence: <1 / 1 000 000
  • Inheritance: X-linked recessive 
  • Age of onset: Neonatal
  • ICD-10: D55.0
  • OMIM: 300908
  • UMLS: C5680005
  • MeSH: -
  • GARD: -
  • MedDRA: -

Detailed information


ERN produced/endorsed by ERN(s)   FSMR produced/endorsed by FSMR(s)
The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.