- Absent septum pellucidum (HP:0001331): Absence of the septum pellucidum (meaning translucent wall in Latin - SP), also known as the ventricle of Sylvius. The septum pellucidum is a thin, triangular double membrane separating the frontal horns of the right and left lateral ventricles of the brain. It extends between the anterior portion of the corpus callosum, and the body of the fornix and its width varies from 1.5 to 3.0 mm. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Epicanthus (HP:0000286): A fold of skin starting above the medial aspect of the upper eyelid and arching downward to cover, pass in front of and lateral to the medial canthus. Evidence: IEA. (OMIM:618500)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: IEA. Frequency: 2/3. (OMIM:618500)
- 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: IEA. Frequency: 1/3. (OMIM:618500)
- Hitchhiker thumb (HP:0001234): With the hand relaxed and the thumb in the plane of the palm, the axis of the thumb forms an angle of at least 90 degrees with the long axis of the hand. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Long philtrum (HP:0000343): Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border. Evidence: IEA. (OMIM:618500)
- Focal impaired awareness seizure (HP:0002384): Focal impaired awareness seizure (or focal seizure with impaired or lost awareness) is a type of focal-onset seizure characterized by some degree (which may be partial) of impairment of the person's awareness of themselves or their surroundings at any point during the seizure. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- 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: 0/3. (PMID:31006513)
- 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: 2/3. (PMID:31006513)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: IEA. (OMIM:618500)
- Hypoplasia of the zygomatic bone (HP:0010669): Underdevelopment of the zygomatic bone. That is, a reduction in size of the zygomatic bone, including the zygomatic process of the temporal bone of the skull, which forms part of the zygomatic arch. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Type I diabetes mellitus (HP:0100651): A chronic condition in which the pancreas produces little or no insulin. Type I diabetes mellitus is manifested by the sudden onset of severe hyperglycemia with rapid progression to diabetic ketoacidosis unless treated with insulin. Evidence: IEA. Frequency: 3/3. (OMIM:618500)
- Elevated circulating alanine aminotransferase concentration (HP:0031964): An abnormally high concentration in the circulation of alanine aminotransferase (ALT). Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Microtia (HP:0008551): Underdevelopment of the external ear. Evidence: IEA. (OMIM:618500)
- Pancreatic aplasia (HP:0100801): Aplasia of the pancreas. Evidence: PCS. Frequency: 3/3. (PMID:31006513)
- 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: 1/3. (PMID:31006513)
- 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: IEA. Frequency: 1/3. (OMIM:618500)
- Diabetes insipidus (HP:0000873): A state of excessive water intake and hypotonic (dilute) polyuria. Diabetes insipidus may be due to failure of vasopressin (AVP) release (central or neurogenic diabetes insipidus) or to a failure of the kidney to respond to AVP (nephrogenic diabetes insipidus). Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:618500)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Neonatal onset (HP:0003623): Onset of signs or symptoms of disease within the first 28 days of life. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: IEA. (OMIM:618500)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- 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:618500)
- Absent gallbladder (HP:0011467): A developmental defect in which the gallbladder fails to form. Evidence: PCS. Frequency: 2/3. (PMID:31006513)
- Elevated gamma-glutamyltransferase level (HP:0030948): Increased level of the enzyme gamma-glutamyltransferase (GGT). GGT is mainly present in kidney, liver, and pancreatic cells, but small amounts are present in other tissues. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: IEA. (OMIM:618500)
- Exocrine pancreatic insufficiency (HP:0001738): Impaired function of the exocrine pancreas associated with a reduced ability to digest foods because of lack of digestive enzymes. Evidence: PCS. Frequency: 2/3. (PMID:31006513)
- 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. (OMIM:618500)
- Small for gestational age (HP:0001518): Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age. Evidence: PCS. Frequency: 2/3. (PMID:31006513)
- 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: IEA. (OMIM:618500)
- 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: 1/3. (PMID:31006513)
- Conductive hearing impairment (HP:0000405): An abnormality of vibrational conductance of sound to the inner ear leading to impairment of sensory perception of sound. Evidence: IEA. (OMIM:618500)
- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: IEA. Frequency: 2/3. (OMIM:618500)
- Neonatal death (HP:0003811): Death within the first 28 days of life. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: PCS. Frequency: 1/3. (PMID:31006513)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:618500)
- 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:31006513)
- Low-set ears (HP:0000369): Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear. Evidence: IEA. Frequency: 2/3. (OMIM:618500)
- Prominent occiput (HP:0000269): Increased convexity of the occiput (posterior part of the skull). Evidence: PCS. Frequency: 1/3. (PMID:31006513)
These phenotypes are associated with the disease holoprosencephaly 12 with or without pancreatic agenesis (OMIM:618500).