- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 2/4. (PMID:23240096)
- Strabismus (HP:0000486): A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error. Evidence: IEA. (OMIM:615219)
- 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: 2/4. (PMID:23240096)
- 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: 1/4. (PMID:23240096)
- 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: 1/4. (PMID:23240096)
- 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: IEA. (OMIM:615219)
- Right atrial enlargement (HP:0030718): Increase in size of the right atrium. Evidence: PCS. Frequency: 1/4. (PMID:23240096)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: IEA. (OMIM:615219)
- Bulbous nose (HP:0000414): Increased volume and globular shape of the anteroinferior aspect of the nose. Evidence: IEA. (OMIM:615219)
- Hydrocephalus (HP:0000238): Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation. Evidence: PCS. Frequency: 4/4. (PMID:23240096)
- Iris coloboma (HP:0000612): A coloboma of the iris. Evidence: IEA. (OMIM:615219)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 4/4. (PMID:23240096)
- Macular hypoplasia (HP:0001104): Underdevelopment of the macula lutea. Evidence: IEA. (OMIM:615219)
- Macrocephaly (HP:0000256): Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium. Evidence: PCS. Frequency: 2/4. (PMID:23240096)
- 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: TAS. (OMIM:615219)
- Posteriorly rotated ears (HP:0000358): A type of abnormal location of the ears in which the position of the ears is characterized by posterior rotation (the superior part of the ears is rotated towards the back of the head, and the inferior part of the ears towards the front). Evidence: IEA. (OMIM:615219)
- Downslanted palpebral fissures (HP:0000494): The palpebral fissure inclination is more than two standard deviations below the mean. Evidence: IEA. (OMIM:615219)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 1/4. (PMID:23240096)
- Rotary nystagmus (HP:0001583): A form of nystagmus in which the eyeball makes rotary motions around the axis. Evidence: PCS. Frequency: 1/4. (PMID:23240096)
- Colpocephaly (HP:0030048): Colpocephaly is an anatomic finding in the brain manifested by occipital horns that are disproportionately enlarged in comparison with other parts of the lateral ventricles. Evidence: IEA. (OMIM:615219)
- Third trimester onset (HP:0034197): This term refers to a phenotypic feature that was first observed prior to birth during the third trimester, which is defined as 28 weeks and zero days (28+0) of gestation and beyond. Evidence: PCS. Frequency: 2/4. (PMID:23240096)
- 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: IEA. Frequency: Very rare (HP:0040284). (OMIM:615219)
- Abnormal facial shape (HP:0001999): An abnormal morphology (form) of the face or its components. Evidence: IEA. (OMIM:615219)
- Lissencephaly (HP:0001339): A spectrum of malformations of cortical development caused by insufficient neuronal migration that subsumes the terms agyria, pachygyria and subcortical band heterotopia. See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly. Evidence: IEA. Frequency: 4/4. (OMIM:615219)
- 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:23240096)
- Optic atrophy (HP:0000648): Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:615219)
- 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: 1/4. (PMID:23240096)
- Alternating esotropia (HP:0001137): Esotropia in which either eye may be used for fixation. Evidence: PCS. Frequency: 1/4. (PMID:23240096)
- Frontal bossing (HP:0002007): Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline. Evidence: IEA. (OMIM:615219)
- Atrial septal defect (HP:0001631): Atrial septal defect (ASD) is a congenital abnormality of the interatrial septum that enables blood flow between the left and right atria via the interatrial septum. Evidence: PCS. Frequency: 1/4. (PMID:23240096)
- Communicating hydrocephalus (HP:0001334): A form of hydrocephalus in which there is no visible obstruction to the flow of the cerebrospinal fluid between the ventricles and subarachnoid space. Evidence: TAS. (OMIM:615219)
- Chorioretinal coloboma (HP:0000567): Absence of a region of the retina, retinal pigment epithelium, and choroid. Evidence: PCS. Frequency: 2/4. (PMID:23240096)
- Simplified gyral pattern (HP:0009879): An abnormality of the cerebral cortex with fewer gyri but with normal cortical thickness. This pattern is usually often associated with congenital microcephaly. Evidence: TAS. (OMIM:615219)
These phenotypes are associated with the disease hydrocephalus, nonsyndromic, autosomal recessive 2 (OMIM:615219).