- Bilateral tonic-clonic seizure (HP:0002069): A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Strabismus (HP:0000486): A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error. Evidence: PCS. Frequency: 5/8. (PMID:33894126)
- Short stature (HP:0004322): A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms). Evidence: PCS. Frequency: 3/8. (PMID:33894126)
- 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: 8/8. (PMID:33894126)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: PCS. Frequency: 3/6. (PMID:33894126)
- Dysgenesis of the hippocampus (HP:0025101): Structural abnormality of the hippocampus related to defective development. Evidence: PCS. Frequency: 2/3. (PMID:33894126)
- Narrow palm (HP:0004283): For children from birth to 4 years of age, the palm width is more than 2 SD below the mean; for children from 4 to 16 years of age the palm width is below the 5th centile; or, the width of the palm appears disproportionately narrow for its length. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Premature anterior fontanel closure (HP:0008491): Early closure (ossification) of the anterior fontanelle, which generally undergoes closure around the 18th month of life. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Aggressive behavior (HP:0000718): Behavior or an act aimed at harming a person, animal, or physical property (e.g., acts of physical violence; shouting, swearing, and using harsh language; slashing someone's tires). Evidence: PCS. Frequency: 4/7. (PMID:33894126)
- Thick vermilion border (HP:0012471): Increased width of the skin of vermilion border region of upper lip. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- 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: PCS. Frequency: 1/6. (PMID:33894126)
- Delayed ability to sit (HP:0025336): A failure to achieve the ability to sit at an appropriate developmental stage. Most children sit with support at 6 months of age and sit steadily without support at 9 months of age. Evidence: PCS. Frequency: 8/8. (PMID:33894126)
- Hip dysplasia (HP:0001385): The presence of developmental dysplasia of the hip. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Micropenis (HP:0000054): Abnormally small penis. At birth, the normal penis is about 3 cm (stretched length from pubic tubercle to tip of penis) with micropenis less than 2.0-2.5 cm. Evidence: PCS. Frequency: 2/3. (PMID:33894126)
- Downslanted palpebral fissures (HP:0000494): The palpebral fissure inclination is more than two standard deviations below the mean. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 6/8. (PMID:33894126)
- Joint hypermobility (HP:0001382): The capability that a joint (or a group of joints) has to move, passively and/or actively, beyond normal limits along physiological axes. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Deeply set eye (HP:0000490): An eye that is more deeply recessed into the plane of the face than is typical. Evidence: PCS. Frequency: 2/6. (PMID:33894126)
- Chorea (HP:0002072): Chorea (Greek for 'dance') refers to widespread arrhythmic involuntary movements of a forcible, jerky and restless fashion. It is a random-appearing sequence of one or more discrete involuntary movements or movement fragments. Movements appear random because of variability in timing, duration or location. Each movement may have a distinct start and end. However, movements may be strung together and thus may appear to flow randomly from one muscle group to another. Chorea can involve the trunk, neck, face, tongue, and extremities. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Tapered finger (HP:0001182): The gradual reduction in girth of the finger from proximal to distal. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Mild fetal ventriculomegaly (HP:0010952): A kind of ventriculomegaly occurring in the fetal period and usually diagnosed by prenatal ultrasound. Cerebral ventriculomegaly is defined by atrial measurements 10 mm or more. Mild ventriculomegaly (MVM) is defined as measurements between 10 and 15 mm. Measurements are obtained from an axial plane at the level of the thalamic nuclei just below the standard image to measure the BPD (PMID:16100637). Evidence: PCS. Frequency: 1/8. Onset: Fetal onset (HP:0011461). (PMID:33894126)
- Autistic behavior (HP:0000729): Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Hip dislocation (HP:0002827): Displacement of the femur from its normal location in the hip joint. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- 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: PCS. Frequency: 2/6. (PMID:33894126)
- 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: 1/6. (PMID:33894126)
- Athetosis (HP:0002305): A slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture. Athetosis involves continuous smooth movements that appear random and are not composed of recognizable sub-movements or movement fragments. In contrast to chorea, in athetosis, the same regions of the body are repeatedly involved. Athetosis may worsen with attempts at movement of posture, but athetosis can also occur at rest. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Focal-onset seizure (HP:0007359): A focal-onset seizure is a type of seizure originating within networks limited to one hemisphere. They may be discretely localized or more widely distributed, and may originate in subcortical structures. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- Short philtrum (HP:0000322): Distance between nasal base and midline upper lip vermilion border more than 2 SD below the mean. Alternatively, an apparently decreased distance between nasal base and midline upper lip vermilion border. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- 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: 1/6. (PMID:33894126)
- 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:33894126)
- Brachycephaly (HP:0000248): An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Narrow palate (HP:0000189): Width of the palate more than 2 SD below the mean (objective) or apparently decreased palatal width (subjective). Evidence: PCS. Frequency: 2/6. (PMID:33894126)
- 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: 8/8. (PMID:33894126)
- Severe intellectual disability (HP:0010864): Severe intellectual disability (ID) is defined as a type of ID characterized by severely sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 20-34. Evidence: PCS. Frequency: 8/8. (PMID:33894126)
- Ulnar deviation of the hand (HP:0009487): Divergence of the longitudinal axis of the hand at the wrist in a posterior (ulnar) direction (i.e., towards the little finger). Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Motor stereotypy (HP:0000733): Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose. Evidence: PCS. Frequency: 2/8. (PMID:33894126)
- 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: PCS. Frequency: 1/8. (PMID:33894126)
- 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: 2/6. (PMID:33894126)
- Wide mouth (HP:0000154): Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective). Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Curly hair (HP:0002212). Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: PCS. Frequency: 6/8. (PMID:33894126)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: PCS. Frequency: 5/8. (PMID:33894126)
- Wide nasal bridge (HP:0000431): Increased breadth of the nasal bridge (and with it, the nasal root). Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Delayed ability to walk (HP:0031936): A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months. Evidence: PCS. Frequency: 8/8. (PMID:33894126)
- Cerebellar hypoplasia (HP:0001321): Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time. Evidence: PCS. Frequency: 6/7. (PMID:33894126)
- Limited knee extension (HP:0003066): Reduced ability to extend (straighten) the knee joint. Evidence: PCS. Frequency: 1/8. (PMID:33894126)
- 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: PCS. Frequency: 8/8. (PMID:33894126)
- Impulsivity (HP:0100710): Acting on the spur of the moment or on a momentary basis without consideration of outcomes; having difficulty establishing or following plans; experiencing a sense of urgency and engaging in behavior that is uninhibited, cannot be inhibited, and is uncontrolled. The possibility of repression is inconceivable. Evidence: PCS. Frequency: 1/7. (PMID:33894126)
- Impaired toileting ability (HP:0031061): This term applies to an individual who requires help transferring to the toilet, cleaning self or who uses bedpan or commode. Evidence: PCS. Frequency: 8/8. (PMID:33894126)
- Decreased fetal movement (HP:0001558): An abnormal reduction in quantity or strength of fetal movements. Evidence: PCS. Frequency: 2/8. Onset: Fetal onset (HP:0011461). (PMID:33894126)
- Plagiocephaly (HP:0001357): Asymmetric head shape, which is usually a combination of unilateral occipital flattening with ipsilateral frontal prominence, leading to rhomboid cranial shape. Evidence: PCS. Frequency: 1/6. (PMID:33894126)
- Cryptorchidism (HP:0000028): Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum. Evidence: PCS. Frequency: 1/3. (PMID:33894126)
These phenotypes are associated with the disease Ritscher-Schinzel syndrome 4 (OMIM:619435).