- Alobar holoprosencephaly (HP:0006988): A type of holoprosencephaly characterized by the presence of a single ventricle and no separation of the cerebral hemisphere. The single midline ventricle is often greatly enlarged. Evidence: PCS. Frequency: 27/83. Onset: Congenital onset (HP:0003577). (PMID:19955556)
- Narrow forehead (HP:0000341): Width of the forehead or distance between the frontotemporales is more than two standard deviations below the mean (objective); or apparently narrow intertemporal region (subjective). Evidence: PCS. Frequency: 14/30. (PMID:19955556)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 2/2. (PMID:11479728;PMID:30855487)
- Sloping forehead (HP:0000340): Inclination of the anterior surface of the forehead from the vertical more than two standard deviations above the mean (objective); or apparently excessive posterior sloping of the forehead in a lateral view. Evidence: PCS. Frequency: 2/30. (PMID:19955556)
- Upslanted palpebral fissure (HP:0000582): The palpebral fissure inclination is more than two standard deviations above the mean for age (objective); or, the inclination of the palpebral fissure is greater than typical for age. Evidence: PCS. Frequency: 29/30. (PMID:19955556)
- 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: PCS. Frequency: 22/30. (PMID:19955556)
- Deep philtrum (HP:0002002): Accentuated, prominent philtral ridges giving rise to an exaggerated groove in the midline between the nasal base and upper vermillion border. Evidence: PCS. Frequency: 14/30. (PMID:19955556)
- Trigonocephaly (HP:0000243): Wedge-shaped, or triangular head, with the apex of the triangle at the midline of the forehead and the base of the triangle at the occiput. Evidence: TAS. (OMIM:609637)
- 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: 1/1. (PMID:30855487)
- 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. (PMID:19955556)
- Arachnoid cyst (HP:0100702): An extra-parenchymal and intra-arachnoidal collection of fluid with a composition similar to that of cerebrospinal fluid. Evidence: PCS. Frequency: 1/1. (PMID:30855487)
- Fetal onset (HP:0011461): Onset prior to birth but after 8 weeks of embryonic development (corresponding to a gestational age of 10 weeks). Evidence: PCS. Frequency: 1/1. (PMID:32695376)
- Hypertelorism (HP:0000316): Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes). Evidence: TAS. (OMIM:609637)
- Lobar holoprosencephaly (HP:0006870): A type of holoprosencephaly in which most of the right and left cerebral hemispheres and lateral ventricles are separated but the most rostral aspect of the telencephalon, the frontal lobes, are fused, especially ventrally. Evidence: PCS. Frequency: 10/83. Onset: Congenital onset (HP:0003577). (PMID:19955556)
- Broad forehead (HP:0000337): Width of the forehead or distance between the frontotemporales is more than two standard deviations above the mean (objective); or apparently increased distance between the two sides of the forehead. Evidence: PCS. Frequency: 2/30. (PMID:19955556)
- 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: 12/94. (PMID:19955556;PMID:30855487)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 1/1. (PMID:30855487)
- 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: 12/69. (PMID:19955556)
- 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:609637)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: PCS. Frequency: 1/1. (PMID:30855487)
- Persistent asymmetrical tonic neck reflex (HP:0032549): Persistence beyond the normal age (roughly the first half of the first year of life) of the asymmetric tonic neck reflex (ATNR), which is an easily elicited primitive reflex in the immediate newborn period. The ATNR refers to the phenomenon whereby when the face of an infant is turned to one side, the ipsilateral arm and leg extend and the contralateral arm and leg flex. This posture has been compared to a typical posture of fencers. Evidence: PCS. Frequency: 1/1. (PMID:30855487)
- Lateral ventricle dilatation (HP:0006956). Evidence: PCS. Frequency: 1/1. (PMID:32695376)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 11/11. (OMIM:609637;PMID:11479728)
- Syntelencephaly (HP:0025670): Syntelencephaly is a rare malformation that consists of an abnormal midline connection of the cerebral hemispheres in the posterior frontal and parietal regions, with interhemispheric separation of the basal forebrain, anterior frontal lobes, and occipital regions. Evidence: PCS. Frequency: 1/1. (PMID:32695376)
- Holoprosencephaly (HP:0001360): Holoprosencephaly is a structural anomaly of the brain in which the developing forebrain fails to divide into two separate hemispheres and ventricles. Evidence: PCS. (PMID:19955556)
- 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: 1/1. (PMID:30855487)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: PCS. Frequency: 11/31. (PMID:19955556;PMID:11479728)
- Camptodactyly (HP:0012385): The distal interphalangeal joint and/or the proximal interphalangeal joint of the fingers or toes cannot be extended to 180 degrees by either active or passive extension. Evidence: PCS. Frequency: 1/1. (PMID:11479728)
- High forehead (HP:0000348): An abnormally increased height of the forehead. Evidence: PCS. Frequency: 5/30. (PMID:19955556)
- Hypotelorism (HP:0000601): Interpupillary distance less than 2 SD below the mean (alternatively, the appearance of an decreased interpupillary distance or closely spaced eyes). Evidence: TAS. (OMIM:609637)
- Semilobar holoprosencephaly (HP:0002507): A type of holoprosencephaly in which the left and right frontal and parietal lobes are fused and the interhemispheric fissure is only present posteriorly. Evidence: PCS. Frequency: 42/83. Onset: Congenital onset (HP:0003577). (PMID:19955556)
- Semilobar holoprosencephaly (HP:0002507): A type of holoprosencephaly in which the left and right frontal and parietal lobes are fused and the interhemispheric fissure is only present posteriorly. Evidence: PCS. Frequency: 1/1. (PMID:11479728)
- Semilobar holoprosencephaly (HP:0002507): A type of holoprosencephaly in which the left and right frontal and parietal lobes are fused and the interhemispheric fissure is only present posteriorly. Evidence: PCS. Frequency: 1/1. (PMID:30855487)
- Macrotia (HP:0000400): Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective). Evidence: PCS. Frequency: 12/30. (PMID:19955556)
- Orofacial cleft (HP:0000202): The presence of a cleft (gap, opening, or groove) in the oral cavity, including cleft of the upper lip and/or cleft of the palate. Cleft of the upper lip is visible as a groove or fissure in the lip, most frequently due to a congenital failure of the maxillary and median nasal processes to fuse. Cleft palate is characterized by a grooved depression or fissure in the roof of the mouth, most often resulting from a congenital failure of the palate to fuse properly. Clefts of the lip and palate can occur individually or together. It is preferable to code each defect separately. Evidence: PCS. Frequency: 7/69. (PMID:19955556)
- Synophrys (HP:0000664): Meeting of the medial eyebrows in the midline. Evidence: PCS. Frequency: 4/30. (PMID:19955556)
- Proptosis (HP:0000520): An eye that is protruding anterior to the plane of the face to a greater extent than is typical. Evidence: PCS. Frequency: 1/1. (PMID:11479728)
- Autosomal dominant inheritance (HP:0000006): 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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:19955556)
- Central diabetes insipidus (HP:0000863): A form of diabetes insipidus related to a failure of vasopressin (AVP) release from the hypothalamus. Evidence: PCS. (PMID:19955556)
These phenotypes are associated with the disease holoprosencephaly 5 (OMIM:609637).