- Poor speech (HP:0002465). Evidence: PCS. Frequency: 4/5. (PMID:17853471)
- 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: 3/7. (PMID:17853471;PMID:18523455)
- 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: 3/5. (PMID:17853471)
- 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: 2/2. (PMID:18523455)
- Prominent fingertip pads (HP:0001212): A soft tissue prominence of the ventral aspects of the fingertips. The term "persistent fetal fingertip pads" is often used as a synonym, but should better not be used because it implies knowledge of history of the patient which often does not exist. Evidence: PCS. Frequency: 5/5. (PMID:17853471)
- 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: 2/5. (PMID:17853471)
- 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: 2/2. (PMID:18523455)
- 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: 0/6. (PMID:10946356)
- Generalized non-motor (absence) seizure (HP:0002121): A generalized non-motor (absence) seizure is a type of a type of dialeptic seizure that is of electrographically generalized onset. It is a generalized seizure characterized by an interruption of activities, a blank stare, and usually the person will be unresponsive when spoken to. Any ictal motor phenomena are minor in comparison to these non-motor features. Evidence: PCS. Frequency: 1/5. (PMID:17853471)
- 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: 3/5. Onset: Childhood onset (HP:0011463). (PMID:17853471)
- 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: 2/2. (PMID:18523455)
- Short nose (HP:0003196): Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip. Evidence: PCS. Frequency: 2/2. (PMID:18523455)
- Flat face (HP:0012368): Absence of concavity or convexity of the face when viewed in profile. Evidence: PCS. Frequency: 2/2. (PMID:18523455)
- 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: 2/2. (PMID:18523455)
- 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: 4/5. (PMID:17853471)
- Anxiety (HP:0000739): Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control. Evidence: PCS. Frequency: 1/5. (PMID:17853471)
- Restlessness (HP:0000711): A state of unease is characterized by diffuse motor activity or motion, which is subject to limited control, nonproductive, or disorganized behavior. Evidence: PCS. Frequency: 1/5. (PMID:17853471)
- 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: 1/5. (PMID:17853471)
- Short attention span (HP:0000736): Reduced attention span characterized by distractibility and impulsivity. Evidence: PCS. Frequency: 3/5. (PMID:17853471)
- Thin upper lip vermilion (HP:0000219): Height of the vermilion of the upper lip in the midline more than 2 SD below the mean. Alternatively, an apparently reduced height of the vermilion of the upper lip in the frontal view (subjective). Evidence: PCS. Frequency: 5/5. (PMID:17853471)
- Agitation (HP:0000713): A state of excessive motor activity that is associated with mental distress or a feeling of substantial unease or inner tension. Distinguished from restlessness by the increased level of emotional distress and negative intensity of the experience. Agitation has a significant level of physical activity that is typically threatening to the self or others. Evidence: PCS. Frequency: 2/5. (PMID:17853471)
- 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: 5/5. (PMID:17853471)
- Hyperactivity (HP:0000752): Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate. Evidence: PCS. Frequency: 1/5. (PMID:17853471)
- 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: PCS. Frequency: 34/34. (PMID:10946356;PMID:9731525;PMID:12884430;PMID:17853471)
- Prominent supraorbital ridges (HP:0000336): Greater than average forward and/or lateral protrusion of the supraorbital portion of the frontal bones. Evidence: PCS. Frequency: 2/5. (PMID:17853471)
- Brisk reflexes (HP:0001348): Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal. Evidence: PCS. Frequency: 2/2. (PMID:18523455)
- Thick upper lip vermilion (HP:0000215): Height of the vermilion of the upper lip in the midline more than 2 SD above the mean. Alternatively, an apparently increased height of the vermilion of the upper lip in the frontal view (subjective). Evidence: PCS. Frequency: 2/2. (PMID:18523455)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 4/7. (PMID:17853471;PMID:18523455)
- Clumsiness (HP:0002312): Lack of physical coordination resulting in an abnormal tendency to drop items or bump into objects. Evidence: PCS. Frequency: 2/2. (PMID:18523455)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: PCS. Frequency: 5/5. (PMID:17853471)
- 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: 2/2. (PMID:18523455)
- Open mouth (HP:0000194): A facial appearance characterized by a permanently or nearly permanently opened mouth. Evidence: PCS. Frequency: 4/5. (PMID:17853471)
- Deeply set eye (HP:0000490): An eye that is more deeply recessed into the plane of the face than is typical. Evidence: PCS. Frequency: 2/5. (PMID:17853471)
- 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: 2/2. (PMID:18523455)
- Delayed gross motor development (HP:0002194): A type of motor delay characterized by a delay in acquiring the ability to control the large muscles of the body for walking, running, sitting, and crawling. Evidence: PCS. Frequency: 1/5. (PMID:17853471)
- Psychosis (HP:0000709): A condition characterized by changes in personality and thought patterns, often accompanied by hallucinations and delusional beliefs, is known as psychosis. Evidence: PCS. Frequency: 1/5. (PMID:17853471)
- X-linked recessive inheritance (HP:0001419): A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele. Evidence: PCS. (PMID:9731525)
- Prominent nasal bridge (HP:0000426): Anterior positioning of the nasal root in comparison to the usual positioning for age. Evidence: PCS. Frequency: 5/5. (PMID:17853471)
- Drooling (HP:0002307): Habitual flow of saliva out of the mouth. Evidence: PCS. Frequency: 4/7. (PMID:17853471;PMID:18523455)
- 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: 13/26. (PMID:12884430;PMID:17853471;PMID:18523455)
These phenotypes are associated with the disease intellectual disability, X-linked 30 (OMIM:300558).