Rare diseases · Sign or symptom
Mental deterioration
Cognitive decline
HP:0001268
What it means
Loss of previously present mental abilities, generally in adults.
Rare diseases that can present with this84
Very common80–99%
19- ABeta amyloidosis, Dutch type
- Amelocerebrohypohidrotic syndrome
- Autosomal recessive spastic paraplegia type 11
- Behavioral variant of frontotemporal dementia
- Childhood disintegrative disorder
- Classic progressive supranuclear palsy syndrome
- Cockayne syndrome
- Developmental malformations-deafness-dystonia syndrome
- Fatty acid hydroxylase-associated neurodegeneration
- Huntington disease
- Infantile Krabbe disease
- Mitochondrial membrane protein-associated neurodegeneration
- Niemann-Pick disease type C
- Nijmegen breakage syndrome
- Progressive non-fluent aphasia
- Richards-Rundle syndrome
- Subacute sclerosing leukoencephalitis
- Woodhouse-Sakati syndrome
- X-linked cerebral adrenoleukodystrophy
Common30–79%
38- ABeta amyloidosis, Italian type
- Acute disseminated encephalomyelitis
- Acute intermittent porphyria
- Atypical progressive supranuclear palsy syndrome
- Autoimmune limbic encephalitis
- Autosomal recessive spastic paraplegia type 21
- Autosomal recessive spastic paraplegia type 35
- Bilateral polymicrogyria
- Chronic neurovisceral acid sphingomyelinase deficiency
- Classic galactosemia
- CNTNAP2-related developmental and epileptic encephalopathy
- Encephalitis lethargica
- Gerstmann-Straussler-Scheinker syndrome
- Homocystinuria due to methylene tetrahydrofolate reductase deficiency
- Ichthyosis follicularis-alopecia-photophobia syndrome
- Lafora disease
- Late-infantile/juvenile Krabbe disease
- Lennox-Gastaut syndrome
- Leukoencephalopathy with calcifications and cysts
- Linear verrucous nevus syndrome
- Megalencephalic leukoencephalopathy with subcortical cysts
- Mitochondrial DNA-related cardiomyopathy and hearing loss
- Mohr-Tranebjaerg syndrome
- Mucopolysaccharidosis type 2
- Myoclonic epilepsy of infancy
- Pantothenate kinase-associated neurodegeneration
- PLA2G6-related neurodegeneration, infantile-onset
- Progressive multifocal leukoencephalopathy
- Progressive supranuclear palsy-corticobasal syndrome
- Progressive supranuclear palsy-predominant parkinsonism syndrome
- Progressive supranuclear palsy-progressive non-fluent aphasia syndrome
- Ring chromosome 20 syndrome
- Sandhoff disease, adult form
- Serotonin syndrome
- Sneddon syndrome
- Spinocerebellar ataxia type 17
- Spinocerebellar ataxia type 7
- Unilateral focal polymicrogyria
Sometimes5–29%
23- 4H leukodystrophy
- Adult Krabbe disease
- Antiphospholipid syndrome
- Ataxia with vitamin E deficiency
- Autosomal dominant cerebellar ataxia-deafness-narcolepsy syndrome
- Cerebral autosomal recessive arteriopathy-subcortical infarcts-leukoencephalopathy
- Choreoacanthocytosis
- Congenital bile acid synthesis defect type 4
and 15 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Cognitive decline, progressive · Intellectual deterioration · Progressive cognitive decline
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.