- Angiokeratoma (HP:0001014): Angiokeratomas are hyperkeratotic papules that are characterized histologically by superficial ectatic (i.e., dilated) blood vessels with epidermal proliferation. Clinically, angiokeratoma presents as a small, raised, dark-red spot. Evidence: TAS. (OMIM:248510)
- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: TAS. (OMIM:248510)
- Abnormal speech pattern (HP:0002167): An abnormality in the sound (volume) or cadence (rate) of speech. Evidence: TAS. (OMIM:248510)
- 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: TAS. Frequency: Occasional (HP:0040283). (OMIM:248510)
- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: TAS. (OMIM:248510)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 1/1. (PMID:18565776)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: TAS. (OMIM:248510)
- Decreased circulating beta-mannosidase activity (HP:0034367): Activity of the enzyme beta-mannosidase below the lower limit of normal. Beta-mannosidase is a lysosomal enzyme that catabolizes oligosaccharides. Evidence: PCS. Frequency: 1/1. (PMID:18565776)
- Increased urinary disaccharide excretion (HP:0012066): Increased concentration of disaccharide in the urine. Evidence: TAS. (OMIM:248510)
- Recurrent infections (HP:0002719): Increased susceptibility to infections as manifested by repeated bouts of infection. Evidence: TAS. (OMIM:248510)
- Aggressive behavior (HP:0000718): Behavior or an act aimed at harming a person, animal, or physical property (e.g., acts of physical violence; shouting, swearing, and using harsh language; slashing someone's tires). Evidence: TAS. (OMIM:248510)
- Abnormal facial shape (HP:0001999): An abnormal morphology (form) of the face or its components. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:248510)
- Tortuosity of conjunctival vessels (HP:0000503): The presence of an increased number of twists and turns of the conjunctival blood vessels. Evidence: TAS. (OMIM:248510)
- 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:9384606)
- Hyperactivity (HP:0000752): Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate. Evidence: PCS. Frequency: 1/1. (PMID:18565776)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: PCS. Frequency: 1/1. (PMID:18565776)
- Reduced tissue beta-mannosidase activity (HP:4000205): Concentration or activity of beta-mannosidase (EC 3.2.1.25) below the lower limit of normal. Beta-mannosidas enzyme can be measured in multiple tissues including leukocytes and cultured fibroblasts. Evidence: PCS. Frequency: 1/1. (PMID:18565776)
- Demyelinating peripheral neuropathy (HP:0007108): Demyelinating neuropathy is characterized by slow nerve conduction velocities with reduced amplitudes of sensory/motor nerve conduction and prolonged distal latencies. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:248510)
These phenotypes are associated with the disease beta-mannosidosis (OMIM:248510).