- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. (PMID:28625504)
- 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: 2/11. (PMID:28625504)
- 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: 2/11. (PMID:28625504)
- Agenesis of corpus callosum (HP:0001274): Absence of the corpus callosum as a result of the failure of the corpus callosum to develop, which can be the result of a failure in any one of the multiple steps of callosal development including cellular proliferation and migration, axonal growth or glial patterning at the midline. Evidence: PCS. Frequency: 0/11. (PMID:28625504)
- 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. (PMID:28625504)
- Gray matter heterotopia (HP:0002282): Heterotopia or neuronal heterotopia are macroscopic clusters of misplaced neurons (gray matter), most often situated along the ventricular walls or within the subcortical white matter. Evidence: PCS. Frequency: 3/11. (PMID:28625504)
- Polydactyly (HP:0010442): A congenital anomaly characterized by the presence of supernumerary fingers or toes. Evidence: PCS. Frequency: 2/10. (PMID:28625504)
- Dandy-Walker malformation (HP:0001305): A congenital brain malformation typically characterized by incomplete formation of the cerebellar vermis, dilation of the fourth ventricle, and enlargement of the posterior fossa. In layman's terms, Dandy Walker malformation is a cyst in the cerebellum (typically symmetrical) that is involved with the fourth ventricle. This may interfere with the ability to drain cerebrospinal fluid from the brain, resulting in hydrocephalus. Dandy Walker cysts are formed during early embryonic development, while the brain forms. The cyst in the cerebellum typically has several blood vessels running through it connecting to the brain, thereby prohibiting surgical removal. Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Molar tooth sign on MRI (HP:0002419): An abnormal appearance of the midbrain in axial magnetic resonance imaging in which the elongated superior cerebellar peduncles give the midbrain an appearance reminiscent of a molar or wisdom tooth. Evidence: PCS. Frequency: 11/11. (PMID:28625504)
- Reduced visual acuity (HP:0007663). Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Thin upper lip vermilion (HP:0000219): Height of the vermilion of the upper lip in the midline more than 2 SD below the mean. Alternatively, an apparently reduced height of the vermilion of the upper lip in the frontal view (subjective). Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 3/11. (PMID:28625504)
- High palate (HP:0000218): Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective). Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- 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: 11/11. (PMID:28625504)
- Retinal dystrophy (HP:0000556): Retinal dystrophy is an abnormality of the retina associated with a hereditary process. Retinal dystrophies are defined by their predominantly monogenic inheritance and they are frequently associated with loss or dysfunction of photoreceptor cells as a primary or secondary event. Evidence: PCS. Frequency: 2/9. (PMID:28625504)
- Micropenis (HP:0000054): Abnormally small penis. At birth, the normal penis is about 3 cm (stretched length from pubic tubercle to tip of penis) with micropenis less than 2.0-2.5 cm. Evidence: PCS. Frequency: 1/6. (PMID:28625504)
- 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: PCS. (PMID:28625504)
- Wide nasal bridge (HP:0000431): Increased breadth of the nasal bridge (and with it, the nasal root). Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Abnormality of eye movement (HP:0000496): An abnormality in voluntary or involuntary eye movements or their control. Evidence: PCS. Frequency: 9/10. (PMID:28625504)
- Postaxial hand polydactyly (HP:0001162): Supernumerary digits located at the ulnar side of the hand (that is, on the side with the fifth finger). Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Superior cerebellar dysplasia (HP:0020185): Abnormal morphological development of the superior part of the cerebellum. Evidence: PCS. Frequency: 11/11. (PMID:28625504)
- Bifid uvula (HP:0000193): Uvula separated into two parts most easily seen at the tip. Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- 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: 11/11. (PMID:28625504)
- 2-3 toe syndactyly (HP:0004691): Syndactyly with fusion of toes two and three. Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Optic nerve hypoplasia (HP:0000609): Underdevelopment of the optic nerve. Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Ptosis (HP:0000508): The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective). Evidence: PCS. Frequency: 7/10. (PMID:28625504)
- 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:28625504)
- Tachypnea (HP:0002789): Very rapid breathing. Evidence: PCS. Frequency: 3/11. (PMID:28625504)
- Apnea (HP:0002104): Lack of breathing with no movement of the respiratory muscles and no exchange of air in the lungs. This term refers to a disposition to have recurrent episodes of apnea rather than to a single event. Evidence: PCS. Frequency: 3/11. (PMID:28625504)
- Coloboma (HP:0000589): A developmental defect characterized by a cleft of some portion of the eye or ocular adnexa. Evidence: PCS. Frequency: 0/8. (PMID:28625504)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: PCS. Frequency: 1/11. (PMID:28625504)
- Polymicrogyria (HP:0002126): Polymicrogyria is a congenital malformation of the cerebral cortex characterized by abnormal cortical layering (lamination) and an excessive number of small gyri (folds). Evidence: PCS. Frequency: 0/11. (PMID:28625504)
These phenotypes are associated with the disease Joubert syndrome 30 (OMIM:617622).