- Progressive (HP:0003676): Applies to a disease manifestation that increases in scope or severity over the course of time, i.e., that worsens with age. Evidence: TAS. (OMIM:615191)
- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:615191)
- Hypoplasia of the brainstem (HP:0002365): Underdevelopment of the brainstem. Evidence: PCS. Frequency: 4/4. (PMID:23472759)
- 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: 4/4. (PMID:23472759)
- Occipital encephalocele (HP:0002085): A type of encephalocele (that is, a a protrusion of part of the cranial contents including brain tissue through a congenital opening in the cranium, typically covered with skin or mucous membrane) in the occipital region of the skull. Occipital encephalocele presents as a midline swelling over the occipital bone. It is usually covered with normal full-thickness scalp. Evidence: PCS. Frequency: 3/4. (PMID:23472759)
- 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: 3/4. (PMID:23472759)
- 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: TAS. (PMID:23472759)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 4/4. (PMID:23472759)
- Type II lissencephaly (HP:0007260): A form of lissencephaly characterized by an uneven cortical surface with a so called 'cobblestone' appearace. There are no distinguishable cortical layers. Evidence: PCS. Frequency: 4/4. (PMID:23472759)
- Cerebellar hemisphere hypoplasia (HP:0100307). Evidence: PCS. Frequency: 4/4. (PMID:23472759)
- Cataract (HP:0000518): A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:615191)
- 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:23472759)
- 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: TAS. (OMIM:615191)
- 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: 4/4. (PMID:23472759)
- Cerebellar vermis hypoplasia (HP:0001320): Underdevelopment of the vermis of cerebellum. Evidence: PCS. Frequency: 4/4. (PMID:23472759)
- Subcortical band heterotopia (HP:0032409): A form of subcortical heterotopia with mislocalized gray matter within the white matter.It is defined as longitudinal bands of gray matter located deep to the cerebral cortex and separated from it by a thin layer of normal appearing white matter. It is part of the lissencephaly spectrum. Evidence: IEA. (OMIM:615191)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: PCS. Frequency: 3/4. (PMID:23472759)
- Porencephalic cyst (HP:0002132): A cavity within the cerebral hemisphere, filled with cerebrospinal fluid, that communicates directly with the ventricular system. Evidence: TAS. (OMIM:615191)
- 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: TAS. (OMIM:615191)
- 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: IEA. (OMIM:615191)
- Severe global developmental delay (HP:0011344): A severe delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: TAS. (OMIM:615191)
- 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:23472759)
- 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: PCS. Frequency: 2/4. (PMID:23472759)
- Spastic paraplegia (HP:0001258): Complete loss of the ability to move the lower limbs accompanied by spasticity of the lower limbs. Evidence: TAS. (OMIM:615191)
- Abnormal cerebral white matter morphology (HP:0002500): An abnormality of the cerebral white matter. Evidence: PCS. Frequency: 4/4. (PMID:23472759)
These phenotypes are associated with the disease cobblestone lissencephaly without muscular or ocular involvement (OMIM:615191).