- 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: PCS. Frequency: 1/3. (PMID:15805158)
- Biparietal narrowing (HP:0004422): A narrowing of the biparietal diameter (i.e., of the transverse distance between the protuberances of the two parietal bones of the skull). Evidence: IEA. (OMIM:605309)
- 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:605309)
- 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: 1/3. (PMID:15805158)
- 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: IEA. (OMIM:605309)
- Hepatomegaly (HP:0002240): Abnormally increased size of the liver. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:605309)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 3/3. (PMID:15805158)
- Postnatal macrocephaly (HP:0005490): The postnatal development of an abnormally large skull (macrocephaly). Evidence: PCS. Frequency: 3/3. (PMID:15805158)
- Penile freckling (HP:0031447): Multiple pigmented macules located on the skin of the penis. Evidence: PCS. Frequency: 2/3. (PMID:15805158)
- Recurrent infections (HP:0002719): Increased susceptibility to infections as manifested by repeated bouts of infection. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:605309)
- Prominent forehead (HP:0011220): Forward prominence of the entire forehead, due to protrusion of the frontal bone. Evidence: PCS. Frequency: 2/3. (PMID:15805158)
- Autism (HP:0000717): Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV). Evidence: PCS. Frequency: 3/3. (PMID:15805158)
- Overgrowth (HP:0001548): Excessive postnatal growth which may comprise increased weight, increased length, and/or increased head circumference. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- 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: IEA. (OMIM:605309)
- Decreased total lymphocyte count (HP:0001888): A reduced number of lymphocytes in the blood. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:605309)
- Short attention span (HP:0000736): Reduced attention span characterized by distractibility and impulsivity. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- 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: 1/3. (PMID:15805158)
- 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: IEA. (OMIM:605309)
- Splenomegaly (HP:0001744): Abnormal increased size of the spleen. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:605309)
- Cutis laxa (HP:0000973): Wrinkled, redundant, inelastic and sagging skin. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Decreased circulating immunoglobulin concentration (HP:0004313): An abnormally decreased level of immunoglobulin in blood. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:605309)
- 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: 2/3. (PMID:15805158)
- Large for gestational age (HP:0001520): The term large for gestational age applies to babies whose birth weight lies above the 90th percentile for that gestational age. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Hydrocele testis (HP:0000034): Accumulation of clear fluid in the between the layers of membrane (tunica vaginalis) surrounding the testis. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- 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: 1/3. (PMID:15805158)
- 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: 2/3. (PMID:15805158)
- Midface retrusion (HP:0011800): Posterior positions and/or vertical shortening of the infraorbital and perialar regions, or increased concavity of the face and/or reduced nasolabial angle. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Dilation of Virchow-Robin spaces (HP:0012520): Increased dimensions of the Virchow-Robin spaces (also known as perivascular spaces), which surround the walls of vessels as they course from the subarachnoid space through the brain parenchyma. Perivascular spaces are commonly microscopic, and not visible on conventional neuroimaging. This term refers to an increase of size of these spaces such that they are visible on neuroimaging (usually magnetic resonance imaging). The dilatations are regular cavities that always contain a patent artery. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Speech apraxia (HP:0011098): A type of apraxia that is characterized by difficulty or inability to execute speech movements because of problems with coordination and motor problems, leading to incorrect articulation. An increase of errors with increasing word and phrase length may occur. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Recurrent otitis media (HP:0000403): Increased susceptibility to otitis media, as manifested by recurrent episodes of otitis media. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Coarse hair (HP:0002208): Hair shafts are rough in texture. Evidence: PCS. Frequency: 1/3. (PMID:15805158)
- Frontal bossing (HP:0002007): Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline. Evidence: TAS. (OMIM:605309)
- 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:15805158)
- Obesity (HP:0001513): Accumulation of substantial excess body fat. Evidence: IEA. (OMIM:605309)
These phenotypes are associated with the disease macrocephaly-autism syndrome (OMIM:605309).