- Cerebral atrophy (HP:0002059): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: IEA. (OMIM:600143)
- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 5/6. (PMID:15024724)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: IEA. (OMIM:600143)
- EEG abnormality (HP:0002353): Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp. Evidence: IEA. (OMIM:600143)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: PCS. Frequency: 6/6. (PMID:15024724)
- Seizure (HP:0001250): A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Evidence: PCS. Frequency: 6/6. (PMID:15024724)
- Cerebellar atrophy (HP:0001272): Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event. Evidence: IEA. (OMIM:600143)
- Increased neuronal autofluorescent lipopigment (HP:0002074): Lipofuscin, a generic term applied to autofluorescent lipopigment, is a mixture of protein and lipid that accumulates in most aging cells, particularly those involved in high lipid turnover (e.g., the adrenal medulla) or phagocytosis of other cell types (e g., the retinal pigment epithelium or RPE; macrophage). This term pertains if there is an increase in the neuronal accumulation of lipofuscin (also known as autofluorescent lipoprotein) more than expected for the age of the patient. Evidence: IEA. (OMIM:600143)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: PCS. Frequency: 5/5. (PMID:15024724)
- Progressive visual loss (HP:0000529): A reduction of previously attained ability to see. Evidence: PCS. Frequency: 6/6. (PMID:15024724)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 1/6. (PMID:15024724)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:15024724)
- Fingerprint intracellular accumulation of autofluorescent lipopigment storage material (HP:0003208): An intracellular accumulation of autofluorescent lipopigment storage material in a trabecular or fingerprint-like pattern. Evidence: PCS. Frequency: 6/6. (PMID:15024724)
- Loss of ambulation (HP:0002505): Inability to walk in a person who previous had the ability to walk. Evidence: PCS. Frequency: 3/3. Onset: Juvenile onset (HP:0003621). (PMID:15024724)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. Frequency: 4/4. (PMID:15024724)
- Curvilinear intracellular accumulation of autofluorescent lipopigment storage material (HP:0003205): An intracellular accumulation of autofluorescent lipopigment storage material in a curved pattern. Evidence: IEA. (OMIM:600143)
These phenotypes are associated with the disease neuronal ceroid lipofuscinosis 8 (OMIM:600143).