- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:228402)
- Open mouth (HP:0000194): A facial appearance characterized by a permanently or nearly permanently opened mouth. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Everted lower lip vermilion (HP:0000232): An abnormal configuration of the lower lip such that it is turned outward i.e., everted, with the Inner aspect of the lower lip vermilion (normally opposing the teeth) being visible in a frontal view. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Malar flattening (HP:0000272): Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Coarse facial features (HP:0000280): Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Synophrys (HP:0000664): Meeting of the medial eyebrows in the midline. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:228402)
- Paroxysmal bursts of laughter (HP:0000749). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:228402)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:228402)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Hip dysplasia (HP:0001385): The presence of developmental dysplasia of the hip. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:228402)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Macrodontia (HP:0001572): Increased size of the teeth, which can be defined as a mesiodistal tooth diameter (width) more than 2 SD above mean for age. Alternatively, an apparently increased maximum width of the tooth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:228402)
- Sandal gap (HP:0001852): A widely spaced gap between the first toe (the great toe) and the second toe. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Constipation (HP:0002019): Infrequent or difficult evacuation of feces. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Generalized hirsutism (HP:0002230): Abnormally increased hair growth over much of the entire body. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Sleep disturbance (HP:0002360): An abnormal pattern in the quality, quantity, or characteristics of sleep. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Highly arched eyebrow (HP:0002553): Increased height of the central portion of the eyebrow, forming a crescent, semicircular, or inverted U shape. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Polyphagia (HP:0002591): A neurological anomaly with gross overeating associated with an abnormally strong desire or need to eat. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Clinodactyly of the 5th finger (HP:0004209): Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Short palm (HP:0004279): Short palm. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- Hypoplasia of penis (HP:0008736). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:228402)
- Tented upper lip vermilion (HP:0010804): Triangular appearance of the oral aperture with the apex in the midpoint of the upper vermilion and the lower vermilion forming the base. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:228402)
- Self-injurious behavior (HP:0100716): Self-aggression. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:228402)
These phenotypes are associated with the disease 2q23.1 microdeletion syndrome (ORPHA:228402).