Acatalasia (acatalasemia; catalase deficiency) is a rare autosomal recessive disorder caused by biallelic CAT variants that reduce or abolish catalase activity. Catalase decomposes hydrogen peroxide to water and oxygen; deficiency impairs hydrogen peroxide catabolism, increases oxidative stress, and can present with gangrenous oral ulcerations, gangrenous periodontitis, loose dentition, and premature tooth loss. Published reviews also associate inherited catalase deficiency with increased risk of type 2 diabetes mellitus, especially in females, likely through chronic hydrogen peroxide/oxidative stress burden.
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name: Acatalasia
creation_date: "2026-07-06T06:09:44Z"
description: >-
Acatalasia (acatalasemia; catalase deficiency) is a rare autosomal recessive
disorder caused by biallelic CAT variants that reduce or abolish catalase
activity. Catalase decomposes hydrogen peroxide to water and oxygen; deficiency
impairs hydrogen peroxide catabolism, increases oxidative stress, and can
present with gangrenous oral ulcerations, gangrenous periodontitis, loose
dentition, and premature tooth loss. Published reviews also associate inherited
catalase deficiency with increased risk of type 2 diabetes mellitus,
especially in females, likely through chronic hydrogen peroxide/oxidative
stress burden.
category: Metabolic Disorder
parents:
- Inborn Error of Metabolism
- Disorder of Hydrogen Peroxide Metabolism
synonyms:
- Acatalasemia
- Catalase deficiency
- CAT deficiency
- Takahara disease
classifications:
icimd_category:
- classification_value: intermediary_metabolism_miscellaneous
notes: >-
ICIMD category 13.2, other miscellaneous/unassigned disorders of
intermediary metabolism. CAT deficiency disrupts hydrogen peroxide
metabolism rather than glyoxylate/oxalate metabolism.
disease_term:
preferred_term: acatalasia
term:
id: MONDO:0013571
label: acatalasia
inheritance:
- name: Autosomal recessive inheritance
inheritance_term:
preferred_term: Autosomal recessive inheritance
term:
id: HP:0000007
label: Autosomal recessive inheritance
evidence:
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Acatalasemia is a very rare disorder characterized by gangrenous oral ulcerations and is caused by biallelic variants in the CAT gene"
explanation: Supports biallelic CAT variants and the recessive disease model.
pathophysiology:
- name: CAT Catalase Deficiency
description: >-
Biallelic CAT variants reduce catalase enzyme activity, impairing the
conversion of hydrogen peroxide to water and oxygen.
role: trigger
genes:
- preferred_term: CAT
term:
id: hgnc:1516
label: CAT
molecular_functions:
- preferred_term: catalase activity
term:
id: GO:0004096
label: catalase activity
modifier: DECREASED
cellular_components:
- preferred_term: peroxisome
term:
id: GO:0005777
label: peroxisome
biological_processes:
- preferred_term: hydrogen peroxide catabolic process
term:
id: GO:0042744
label: hydrogen peroxide catabolic process
modifier: DECREASED
evidence:
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "biallelic variants in the CAT gene which encodes the catalase enzyme that decomposes the hydrogen peroxide molecules to remove their toxic effect."
explanation: Supports CAT variants and catalase-mediated hydrogen peroxide decomposition.
- reference: PMID:1999334
supports: SUPPORT
evidence_source: OTHER
snippet: "in the acatalasemic gene causes a splicing mutation and hence a deficiency of mRNA."
explanation: Historical molecular review supports catalase gene defects as the cause of acatalasemia.
downstream:
- target: Impaired Hydrogen Peroxide Detoxification
causal_link_type: DIRECT
description: Reduced catalase activity impairs hydrogen peroxide catabolism.
- name: Impaired Hydrogen Peroxide Detoxification
description: >-
Catalase deficiency leaves hydrogen peroxide less efficiently decomposed,
increasing the oxidant burden on oral tissues, blood, and metabolically
active tissues.
role: amplifier
biological_processes:
- preferred_term: hydrogen peroxide catabolic process
term:
id: GO:0042744
label: hydrogen peroxide catabolic process
modifier: DECREASED
- preferred_term: response to oxidative stress
term:
id: GO:0006979
label: response to oxidative stress
modifier: INCREASED
chemical_entities:
- preferred_term: hydrogen peroxide
term:
id: CHEBI:16240
label: hydrogen peroxide
modifier: INCREASED
- preferred_term: reactive oxygen species
term:
id: CHEBI:26523
label: reactive oxygen species
modifier: INCREASED
evidence:
- reference: PMID:22365890
supports: SUPPORT
evidence_source: OTHER
snippet: "The enzyme catalase catalyzes the breakdown of hydrogen peroxide into oxygen and water. It is the main regulator of hydrogen peroxide metabolism."
explanation: Supports the hydrogen peroxide detoxification role of catalase.
- reference: PMID:22365890
supports: SUPPORT
evidence_source: OTHER
snippet: "Excessive concentrations may cause significant damages to protein, DNA, RNA and lipids."
explanation: Supports oxidative macromolecular damage as the consequence of excess hydrogen peroxide.
downstream:
- target: Gangrenous Oral and Periodontal Tissue Injury
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
description: Accumulated hydrogen peroxide and oxidative stress injure oral and periodontal tissues.
- target: Diabetes Mellitus Susceptibility
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: Inherited catalase deficiency has been associated with increased type 2 diabetes risk.
- name: Gangrenous Oral and Periodontal Tissue Injury
description: >-
Acatalasia can manifest as gangrenous oral ulcerations and periodontitis,
with loose dentition and premature tooth loss in affected individuals.
role: consequence
cell_types:
- preferred_term: gingival epithelial cell
term:
id: CL:0002621
label: gingival epithelial cell
locations:
- preferred_term: mouth
term:
id: UBERON:0000165
label: mouth
evidence:
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Acatalasemia is a very rare disorder characterized by gangrenous oral ulcerations"
explanation: Supports gangrenous oral ulcerations as a core manifestation.
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "two siblings from a consanguineous Egyptian family presenting with joint hyperlaxity, loose dentitions with gangrenous periodontitis, and early loss of teeth."
explanation: Supports periodontal injury and tooth loss in recent affected siblings.
- name: Diabetes Mellitus Susceptibility
description: >-
Reviews of acatalasemia and diabetes propose that inherited catalase
deficiency can increase type 2 diabetes risk, especially in females, through
chronic hydrogen peroxide and oxidative stress.
role: consequence
evidence:
- reference: PMID:22365890
supports: SUPPORT
evidence_source: OTHER
snippet: "Inherited catalase deficiency may increase the risk of type 2 diabetes mellitus, especially for females."
explanation: Supports type 2 diabetes susceptibility as an associated downstream phenotype.
phenotypes:
- category: Clinical
name: Gangrenous oral ulcerations
description: Gangrenous oral ulcerations are a classic manifestation of acatalasia.
phenotype_term:
preferred_term: Oral ulcer
term:
id: HP:0000155
label: Oral ulcer
evidence:
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Acatalasemia is a very rare disorder characterized by gangrenous oral ulcerations"
explanation: Supports oral ulcerations in acatalasia.
- category: Clinical
name: Abnormality of the gingiva
description: Gangrenous periodontitis reflects severe gingival/periodontal tissue involvement.
phenotype_term:
preferred_term: Abnormality of the gingiva
term:
id: HP:0000168
label: Abnormality of the gingiva
evidence:
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "loose dentitions with gangrenous periodontitis"
explanation: Supports gingival/periodontal involvement.
- category: Clinical
name: Premature loss of teeth
description: Early tooth loss was reported in affected siblings with CAT-related acatalasia.
phenotype_term:
preferred_term: Premature loss of teeth
term:
id: HP:0006480
label: Premature loss of teeth
evidence:
- reference: PMID:39079473
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Premature loss of teeth is an emerging finding in our cases"
explanation: Supports premature tooth loss as an emerging acatalasia manifestation.
- category: Clinical
name: Type 2 diabetes mellitus susceptibility
description: Inherited catalase deficiency has been associated with increased type 2 diabetes risk.
evidence:
- reference: PMID:22365890
supports: SUPPORT
evidence_source: OTHER
snippet: "Inherited catalase deficiency may increase the risk of type 2 diabetes mellitus, especially for females."
explanation: Supports type 2 diabetes susceptibility as an associated phenotype.
notes: >-
Package seed 13.2.01.01; OMIM:614097; ORPHA:926. This entry uses the MONDO
label "acatalasia" as the canonical disease name, with catalase deficiency and
acatalasemia retained as synonyms.