- Delayed CNS myelination (HP:0002188): Delayed myelination in the central nervous system. Evidence: PCS. Frequency: 3/3. (PMID:32533184)
- Biconcave vertebral bodies (HP:0004586): Exaggerated concavity of the anterior or posterior surface of the vertebral body, i.e., the upper and lower vertebral endplates are hollowed inward. Evidence: PCS. Frequency: 2/3. (PMID:32533184)
- Short stature (HP:0004322): A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms). Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- 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: PCS. Frequency: 2/4. (PMID:33668384;PMID:32533184)
- 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: 1/3. (PMID:32533184)
- Macular geographic atrophy (HP:0031609): Chronic progressive degeneration of the macula that can be seen as part of late-stage age-related macular degeneration (AMD). Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- 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: 3/4. (PMID:33668384;PMID:32533184)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 3/3. (PMID:32533184)
- 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: PCS. Frequency: 1/1. (PMID:33668384)
- Brain atrophy (HP:0012444): Partial or complete wasting (loss) of brain tissue that was once present. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Widened cerebellar subarachnoid space (HP:0012765): An increase in size of the anatomic space between the arachnoid membrane and pia mater in the region surrounding the cerebellum. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Cataract (HP:0000518): A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Irregular dentition (HP:0040079). Evidence: PCS. Frequency: 2/3. (PMID:32533184)
- High hypermetropia (HP:0008499): A severe form of hypermetropia with over +5.00 diopters. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- CNS hypomyelination (HP:0003429): Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis. Evidence: PCS. Frequency: 3/4. (PMID:33668384;PMID:32533184)
- Cervical myelopathy (HP:0002318): A collection of pathologic conditions that result from progressive spinal cord dysfunction secondary to cord compression in the cervical spine. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Macular atrophy (HP:0007401): A nonspecific term denoting wasting, especially as a result of degeneration, of the retinal pigment epithelium (RPE) and neurosensory retinal cells in the macula. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Attenuation of retinal blood vessels (HP:0007843): Narrowing of the retinal blood vessels, both arterioles and venules. Evidence: PCS. Frequency: 2/4. (PMID:33668384;PMID:32533184)
- Exotropia (HP:0000577): A form of strabismus with one or both eyes deviated outward. Evidence: PCS. Frequency: 2/3. (PMID:32533184)
- Spondyloepiphyseal dysplasia (HP:0002655): A disorder of bone growth affecting the vertebrae and the ends of the long bones (epiphyses). Evidence: PCS. Frequency: 4/4. (PMID:33668384;PMID:32533184)
- Undetectable electroretinogram (HP:0000550): Lack of any response to stimulation upon electroretinography. Evidence: PCS. Frequency: 4/4. (PMID:33668384;PMID:32533184)
- Wide mouth (HP:0000154): Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective). Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Os odontoideum (HP:0005667): Separation of the odontoid process from the body of the axis. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Cerebral atrophy (HP:0002059): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: PCS. Frequency: 2/3. (PMID:32533184)
- Abnormal auditory evoked potentials (HP:0006958): An abnormality of the auditory evoked potentials, which are used to trace the signal generated by a sound, from the cochlear nerve, through the lateral lemniscus, to the medial geniculate nucleus, and to the cortex. Evidence: PCS. Frequency: 2/2. (PMID:32533184)
- Delayed ability to walk (HP:0031936): A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months. Evidence: PCS. Frequency: 3/3. (PMID:32533184)
- Delayed skeletal maturation (HP:0002750): A decreased rate of skeletal maturation. Delayed skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Leukoencephalopathy (HP:0002352): This term describes abnormality of the white matter of the cerebrum resulting from damage to the myelin sheaths of nerve cells. Evidence: PCS. Frequency: 2/4. (PMID:33668384;PMID:32533184)
- 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: 4/4. (PMID:33668384;PMID:32533184)
- Tetraparesis (HP:0002273): Weakness of all four limbs. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- High myopia (HP:0011003): A severe form of myopia with greater than -6.00 diopters. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Dyskinesia (HP:0100660): A movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Sensorineural hearing impairment (HP:0000407): A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve. Evidence: PCS. Frequency: 4/4. (PMID:33668384;PMID:32533184)
- Irregular epiphyses (HP:0010582): An alteration of the normally smooth contour of the epiphysis leading to an irregular appearance. Evidence: PCS. Frequency: 3/3. (PMID:32533184)
- 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:32533184)
- Retinal degeneration (HP:0000546): A nonspecific term denoting progressive loss of the retinal pigment epithelium (RPE) and/or neurosensory retinal cells. Evidence: PCS. Frequency: 1/1. (PMID:33668384)
- Visual impairment (HP:0000505): Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery. Evidence: PCS. Frequency: 3/3. (PMID:32533184)
- Optic disc pallor (HP:0000543): A pale yellow discoloration of the optic disc (the area of the optic nerve head in the retina). The optic disc normally has a pinkish hue with a central yellowish depression. Evidence: PCS. Frequency: 2/4. (PMID:33668384;PMID:32533184)
- Synophrys (HP:0000664): Meeting of the medial eyebrows in the midline. Evidence: PCS. Frequency: 1/3. (PMID:32533184)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: PCS. Frequency: 4/4. (PMID:33668384;PMID:32533184)
- Macular pseudocoloboma (HP:0001116): A so-called macular coloboma is characterized by a sharply defined, usually excavated, area without neuroretina and RPE tissues in the central area of the fundus. This lesion is not related to classical colobomas associated with optic fissure closure defects. Evidence: PCS. Frequency: 3/4. (PMID:33668384;PMID:32533184)
These phenotypes are associated with the disease spondyloepiphyseal dysplasia, sensorineural hearing loss, impaired intellectual development, and leber congenital amaurosis (OMIM:619260).