- Severe short stature (HP:0003510): A severe degree of short stature, more than -4 SD from the mean corrected for age and sex. Evidence: IEA. (OMIM:230500)
- Hypertonia (HP:0001276): A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move. Evidence: PCS. Frequency: 3/111. (PMID:18524657)
- Inguinal hernia (HP:0000023): Protrusion of the contents of the abdominal cavity through the inguinal canal. Evidence: IEA. (OMIM:230500)
- 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: 10/115. (PMID:18524657)
- 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: PCS. Frequency: 111/115. (PMID:18524657;PMID:22234367)
- Cherry red spot of the macula (HP:0010729): Pallor of the perifoveal macula of the retina with appearance of a small circular reddish choroid shape as seen through the fovea centralis due to relative transparency of the macula. Evidence: PCS. Frequency: 50/84. (PMID:18524657)
- Hepatomegaly (HP:0002240): Abnormally increased size of the liver. Evidence: PCS. Frequency: 104/122. (PMID:18524657)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 4/4. (PMID:22234367)
- Coarse facial features (HP:0000280): Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues. Evidence: IEA. Frequency: 4/4. (OMIM:230500)
- Angiokeratoma corporis diffusum (HP:0001071): Angiokeratoma corporis diffusum (ACD) is typically characterized by innumerable small red to black papules which occur in clusters and are situated symmetrically in the bathing trunks area. The number of lesions and the extension of the body increase steadily with time so that generalization and mucosal involvement are common. The single lesion begins with a minute reddish papule which enlarges to up to 10 mm in diameter, becomes dark red to black with a discrete keratotic overgrowth. Histologically, the papules are characterized by superficial dilated capillaries in papillary dermis with epidermal proliferation. Evidence: IEA. (OMIM:230500)
- Hypertelorism (HP:0000316): Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes). Evidence: IEA. (OMIM:230500)
- Hypertrichosis (HP:0000998): Hypertrichosis is increased hair growth that is abnormal in quantity or location. Evidence: IEA. (OMIM:230500)
- Vacuolated lymphocytes (HP:0001922): The presence of clear, sharply defined vacuoles in the lymphocyte cytoplasm. Evidence: PCS. (PMID:18524657)
- Hydrops fetalis (HP:0001789): The abnormal accumulation of fluid in two or more fetal compartments, including ascites, pleural effusion, pericardial effusion, and skin edema. Evidence: PCS. Frequency: 8/130. (PMID:18524657)
- Hypoplastic vertebral bodies (HP:0008479). Evidence: IEA. (OMIM:230500)
- Death in infancy (HP:0001522): Death within the first 24 months of life. Evidence: IEA. (OMIM:230500)
- Gingival overgrowth (HP:0000212): Hyperplasia of the gingiva (that is, a thickening of the soft tissue overlying the alveolar ridge. The degree of thickening ranges from involvement of the interdental papillae alone to gingival overgrowth covering the entire tooth crown. Evidence: IEA. (OMIM:230500)
- Depressed nasal ridge (HP:0000457): Lack of prominence of the nose resulting from a posteriorly-placed nasal ridge. Evidence: IEA. (OMIM:230500)
- 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: 119/119. (PMID:18524657;PMID:22234367)
- Splenomegaly (HP:0001744): Abnormal increased size of the spleen. Evidence: PCS. Frequency: 104/122. (PMID:18524657)
- Dilated cardiomyopathy (HP:0001644): Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular dilatation and left ventricular systolic dysfunction in the absence of abnormal loading conditions (hypertension, valve disease) or coronary artery disease sufficient to cause global systolic impairment. Right ventricular dilation and dysfunction may be present but are not necessary for the diagnosis. Evidence: IEA. (OMIM:230500)
- Abnormality of the urinary system (HP:0000079): An abnormality of the urinary system. Evidence: IEA. (OMIM:230500)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: IEA. (OMIM:230500)
- Joint stiffness (HP:0001387): Joint stiffness is a perceived sensation of tightness in a joint or joints when attempting to move them after a period of inactivity. Joint stiffness typically subsides over time. Evidence: IEA. (OMIM:230500)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: PCS. Frequency: 119/119. (PMID:18524657;PMID:22234367)
- Short neck (HP:0000470): Diminished length of the neck. Evidence: IEA. (OMIM:230500)
- Hypertrophic cardiomyopathy (HP:0001639): Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality. Evidence: IEA. (OMIM:230500)
- Kyphosis (HP:0002808): Exaggerated anterior convexity of the thoracic vertebral column. Evidence: IEA. (OMIM:230500)
- Decreased beta-galactosidase activity (HP:0008166): Abnormally decreased rate of beta-galactosidase activity. Beta-galactosidase activity can be measured in leukocyte, fibroblast, or plasma. Evidence: IEA. (OMIM:230500)
- Dysostosis multiplex (HP:0000943). Evidence: PCS. Frequency: 4/4. (PMID:22234367)
- 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:18524657)
- Congestive heart failure (HP:0001635): The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction. Evidence: IEA. (OMIM:230500)
- Cerebral degeneration (HP:0007313). Evidence: IEA. (OMIM:230500)
- Thickened ribs (HP:0000900): Increased thickness (diameter) of ribs. Evidence: TAS. (OMIM:230500)
- Abnormal heart valve morphology (HP:0001654): Any structural abnormality of a cardiac valve. Evidence: IEA. (OMIM:230500)
- Frontal bossing (HP:0002007): Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline. Evidence: IEA. (OMIM:230500)
- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: PCS. Frequency: 2/130. Onset: Fetal onset (HP:0011461). (PMID:18524657)
- Beaking of vertebral bodies (HP:0004568): Anterior tongue-like protrusions of the vertebral bodies. Evidence: IEA. (OMIM:230500)
These phenotypes are associated with the disease GM1 gangliosidosis type 1 (OMIM:230500).