- Cavum septum pellucidum (HP:0002389): If the two laminae of the septum pellucidum are not fused then a fluid-filled space or cavum is present. The cavum septum pellucidum is present at birth but usually obliterates by the age of 3 to 6 months. It is up to 1cm in width and the walls are parallel. It is an enclosed space and is not part of the ventricular system or connected with the subarachnoid space. Evidence: IEA. (OMIM:304050)
- Delayed CNS myelination (HP:0002188): Delayed myelination in the central nervous system. Evidence: IEA. (OMIM:304050)
- Carcinoma (HP:0030731): A malignant tumor arising from epithelial cells. Carcinomas that arise from glandular epithelium are called adenocarcinomas, those that arise from squamous epithelium are called squamous cell carcinomas, and those that arise from transitional epithelium are called transitional cell carcinomas (NCI Thesaurus). Evidence: IEA. (OMIM:304050)
- 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. (OMIM:304050)
- Profound intellectual disability (HP:0002187): Profound intellectual disability (ID) is defined as a type of ID characterized by profoundly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) below 20. Evidence: IEA. (OMIM:304050)
- 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: IEA. (OMIM:304050)
- Skin tags (HP:0010609): Cutaneous skin tags also known as acrochorda or fibroepithelial polyps are small benign tumors that may either form secondarily over time primarily in areas where the skin forms creases, such as the neck, armpit or groin or may also be present at birth, in which case they usually occur in the periauricular region. Evidence: TAS. (OMIM:304050)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: TAS. (OMIM:304050)
- Infantile spasms (HP:0012469): Infantile spasms represent a subset of "epileptic spasms". Infantile Spasms are epileptic spasms starting in the first year of life (infancy). Evidence: TAS. (OMIM:304050)
- Dilated third ventricle (HP:0007082): An increase in size of the third ventricle. Evidence: IEA. (OMIM:304050)
- Cataract (HP:0000518): A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule. Evidence: IEA. (OMIM:304050)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: IEA. (OMIM:304050)
- Hemivertebrae (HP:0002937): Absence of one half of the vertebral body. Evidence: IEA. (OMIM:304050)
- Lipoma (HP:0012032): Benign neoplasia derived from lipoblasts or lipocytes of white or brown fat. May be angiomatous or hibernomatous. Evidence: TAS. (OMIM:304050)
- Proximal placement of thumb (HP:0009623): Proximal mislocalization of the thumb. Evidence: IEA. (OMIM:304050)
- Postnatal growth retardation (HP:0008897): Slow or limited growth after birth. Evidence: PCS. (OMIM:304050)
- Spina bifida (HP:0002414): Incomplete closure of the embryonic neural tube, whereby some vertebral arches remain unfused and open. The mildest form is spina bifida occulta, followed by meningocele and meningomyelocele. Evidence: IEA. (OMIM:304050)
- Block vertebrae (HP:0003305): Congenital synostosis between two or more adjacent vertebrae (partial or complete fusion of adjacent vertabral bodies). Evidence: IEA. (OMIM:304050)
- Abnormality of the skin (HP:0000951): An abnormality of the skin. Evidence: IEA. (OMIM:304050)
- Hiatus hernia (HP:0002036): The presence of a hernia in which the upper part of the stomach, i.e., mainly the gastric cardia protrudes through the diaphragmatic esophageal hiatus. Evidence: IEA. (OMIM:304050)
- Cleft palate (HP:0000175): Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate). Evidence: IEA. (OMIM:304050)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: IEA. (OMIM:304050)
- Prominence of the premaxilla (HP:0010759): Prominent positioning of the premaxilla in relation to the rest of the maxilla, the facial skeleton, or mandible. Not necessarily caused by an increase in size (hypertrophy of) the premaxilla. Evidence: TAS. (OMIM:304050)
- Bifid ribs (HP:0000892): A bifid rib refers to cleavage of the sternal end of a rib, usually unilateral. Bifid ribs are usually asymptomatic, and are often discovered incidentally by chest x-ray. Evidence: IEA. (OMIM:304050)
- Choroid plexus cyst (HP:0002190): A cyst occurring within the choroid plexus within a cerebral ventricle. Evidence: IEA. (OMIM:304050)
- Epileptic spasm (HP:0011097): A sudden flexion, extension, or mixed extension-flexion of predominantly proximal and truncal muscles that is usually more sustained than a myoclonic movement but not as sustained as a tonic seizure. Limited forms may occur: Grimacing, head nodding, or subtle eye movements. Epileptic spasms frequently occur in clusters. Infantile spasms are the best known form, but spasms can occur at all ages. Evidence: PCS. (OMIM:304050)
- Chiari malformation (HP:0002308): Chiari malformation consists of a downward displacement of the cerebellar tonsils and the medulla through the foramen magnum, sometimes causing hydrocephalus as a result of obstruction of CSF outflow. Evidence: IEA. (OMIM:304050)
- Missing ribs (HP:0000921): A developmental anomaly with absence of one or more ribs. Evidence: PCS. (OMIM:304050)
- Microphthalmia (HP:0000568): A developmental anomaly characterized by abnormal smallness of one or both eyes. Evidence: IEA. (OMIM:304050)
- Partial agenesis of the corpus callosum (HP:0001338): A partial failure of the development of the corpus callosum. Evidence: PCS. (OMIM:304050)
- 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. (OMIM:304050)
- Supernumerary ribs (HP:0005815): The presence of more than 12 rib pairs. Evidence: IEA. (OMIM:304050)
- Butterfly vertebrae (HP:0003316): A butterfly vertebra (sagittal cleft vertebra or anterior rachischisis) is a sagittal defect in the vertebral body caused by failure of fusion of the two lateral chondrification centers during embryogenesis. The name is based on the appearance of the two hemivertebrae emerging as butterfly wings from the central cleft on x-ray. Evidence: IEA. (OMIM:304050)
- Cleft upper lip (HP:0000204): A gap or groove in the upper lip. This is a congenital defect resulting from nonfusion of tissues of the lip during embryonal development. Evidence: IEA. (OMIM:304050)
- Facial asymmetry (HP:0000324): An abnormal difference between the left and right sides of the face. Evidence: IEA. (OMIM:304050)
- Sparse lateral eyebrow (HP:0005338): Decreased density/number and/or decreased diameter of lateral eyebrow hairs. Evidence: TAS. (OMIM:304050)
- Hepatoblastoma (HP:0002884): A kind of neoplasm of the liver that originates from immature liver precursor cells and macroscopically is composed of tissue resembling fetal or mature liver cells or bile ducts. Evidence: IEA. (OMIM:304050)
- Chorioretinal lacunae (HP:0007858): Punched out lesions in the pigmented layer of the retina. Evidence: PCS. (OMIM:304050)
- Retinal detachment (HP:0000541): Separation of the inner layers of the retina (neural retina) from the pigment epithelium. Evidence: IEA. (OMIM:304050)
- Anteverted nares (HP:0000463): Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip). Evidence: TAS. (OMIM:304050)
- 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. (OMIM:304050)
- 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: IEA. (OMIM:304050)
- Recurrent pneumonia (HP:0006532): An increased susceptibility to pneumonia as manifested by a history of recurrent episodes of pneumonia. Evidence: PCS. (OMIM:304050)
- Pachygyria (HP:0001302): Pachygyria is a malformation of cortical development with abnormally wide gyri with sulci 1,5-3 cm apart and abnormally thick cortex measuring more than 5 mm (radiological definition). See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly. Evidence: IEA. (OMIM:304050)
- X-linked dominant inheritance (HP:0001423): A mode of inheritance that is observed for dominant traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked dominant disorders tend to manifest very severely in affected males. The severity of manifestation in females may depend on the degree of skewed X inactivation. Evidence: IEA. (OMIM:304050)
- Hemangioma (HP:0001028): A hemangioma is a benign tumor characterized by blood-filled spaces lined by benign endothelial cells. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma (in contrast to a hemangioma with small endothelial spaces, which is called capillary hemangioma). Evidence: TAS. (OMIM:304050)
- Cerebellar vermis hypoplasia (HP:0001320): Underdevelopment of the vermis of cerebellum. Evidence: IEA. (OMIM:304050)
- Lateral ventricle dilatation (HP:0006956). Evidence: TAS. (OMIM:304050)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: IEA. (OMIM:304050)
- Precocious puberty (HP:0000826): The onset of secondary sexual characteristics before a normal age. Although it is difficult to define normal age ranges because of the marked variation with which puberty begins in normal children, precocious puberty can be defined as the onset of puberty before the age of 8 years in girls or 9 years in boys. Evidence: IEA. (OMIM:304050)
- Rib fusion (HP:0000902): Complete or partial merging of adjacent ribs. Evidence: IEA. (OMIM:304050)
- Teratoma (HP:0009792): The presence of a teratoma. Evidence: TAS. (OMIM:304050)
- Metastatic angiosarcoma (HP:0200059). Evidence: TAS. (OMIM:304050)
- 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: TAS. (OMIM:304050)
- Optic disc coloboma (HP:0000588): A cleft of the optic nerve that extends inferiorly. Evidence: IEA. (OMIM:304050)
These phenotypes are associated with the disease Aicardi syndrome (OMIM:304050).