- Aortic valve stenosis (HP:0001650): The presence of a stenosis (narrowing) of the aortic valve. Evidence: TAS. (OMIM:220220)
- Cranial nerve paralysis (HP:0006824). Evidence: IEA. (OMIM:220220)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: IEA. (OMIM:220220)
- 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: IEA. (OMIM:220220)
- Thinning and bulging of the posterior fossa bones (HP:0000931). Evidence: IEA. (OMIM:220220)
- 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: TAS. (OMIM:220220)
- Vascular dilatation (HP:0002617): An abnormal increase in the diameter of an artery or vein, either as a diffuse dilatation or as a localized, sac-like outpouching of the vessel wall (aneurysm). Evidence: IEA. (OMIM:220220)
- Posterior fossa cyst at the fourth ventricle (HP:0000933). Evidence: IEA. (OMIM:220220)
- Patent ductus arteriosus (HP:0001643): In utero, the ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta by connecting the main pulmonary artery to the descending aorta. A patent ductus arteriosus (PDA) in the first 3 days of life is a physiologic shunt in healthy term and preterm newborn infants, and normally is substantially closed within about 24 hours after bith and completely closed after about three weeks. Failure of physiologcal closure is referred to a persistent or patent ductus arteriosus (PDA). Depending on the degree of left-to-right shunting, PDA can have clinical consequences. Evidence: TAS. (OMIM:220220)
- 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:220220)
- Elevated imprint of the transverse sinuses (HP:0000930). Evidence: IEA. (OMIM:220220)
- Partial absence of cerebellar vermis (HP:0002951): Congenital absence of a part of the vermis of cerebellum. Evidence: TAS. (OMIM:220220)
- Agenesis of cerebellar vermis (HP:0002335): Congenital absence of the vermis of cerebellum. Evidence: TAS. (OMIM:220220)
- Chorioretinal atrophy (HP:0000533): Atrophy (wasting) of the choroid and retinal layers of the fundus. Evidence: TAS. (OMIM:220220)
- Truncal ataxia (HP:0002078): Truncal ataxia is a sign of ataxia characterized by instability of the trunk. It usually occurs during sitting. Evidence: IEA. (OMIM:220220)
- Wide nasal bridge (HP:0000431): Increased breadth of the nasal bridge (and with it, the nasal root). Evidence: TAS. (OMIM:220220)
- Postaxial hand polydactyly (HP:0001162): Supernumerary digits located at the ulnar side of the hand (that is, on the side with the fifth finger). Evidence: IEA. (OMIM:220220)
- Dilated fourth ventricle (HP:0002198): An abnormal dilatation of the fourth cerebral ventricle. Evidence: IEA. (OMIM:220220)
- Narrow palpebral fissure (HP:0045025): Reduction in the vertical distance between the upper and lower eyelids. Evidence: TAS. (OMIM:220220)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: TAS. (OMIM:220220)
- Posterior embryotoxon (HP:0000627): A posterior embryotoxon is the presence of a prominent and anteriorly displaced line of Schwalbe. Evidence: TAS. (OMIM:220220)
- Microretrognathia (HP:0000308): A form of developmental hypoplasia of the mandible in which the mandible is mislocalised posteriorly. Evidence: TAS. (OMIM:220220)
- 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: TAS. (OMIM:220220)
- Frontal bossing (HP:0002007): Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline. Evidence: TAS. (OMIM:220220)
- Dolichocephaly (HP:0000268): An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture. Evidence: TAS. (OMIM:220220)
- 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: TAS. (OMIM:220220)
These phenotypes are associated with the disease Dandy-Walker malformation-postaxial polydactyly syndrome (OMIM:220220).