- Arachnodactyly (HP:0001166): Abnormally long and slender fingers (spider fingers). Evidence: PCS. Frequency: 1/7. (PMID:16199551)
- 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: TAS. (OMIM:300263)
- 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: TAS. (OMIM:300263)
- Large hands (HP:0001176). Evidence: TAS. Frequency: 2/7. (OMIM:300263)
- Cleft palate (HP:0000175): Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate). Evidence: PCS. Frequency: 5/8. (PMID:17594395;OMIM:300263)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 1/1. (PMID:17594395)
- 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. (OMIM:300263)
- Mild intellectual disability (HP:0001256): Mild intellectual disability (ID) is defined as a type of ID characterized by mildly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 50-69. Evidence: PCS. Frequency: 7/7. (PMID:16199551)
- Long face (HP:0000276): Facial height (length) is more than 2 standard deviations above the mean (objective); or, an apparent increase in the height (length) of the face (subjective). Evidence: PCS. Frequency: 4/4. (PMID:16199551)
- Low posterior hairline (HP:0002162): Hair on the neck extends more inferiorly than usual. Evidence: TAS. (OMIM:300263)
- Long toe (HP:0010511): Toes that appear disproportionately long compared to the foot. Evidence: TAS. (OMIM:300263)
- Cleft lip (HP:0410030): A gap in the lip or lips. Evidence: PCS. Frequency: 6/8. (PMID:17594395;OMIM:300263)
- 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:16497722)
- Broad nasal tip (HP:0000455): Increase in width of the nasal tip. Evidence: TAS. Frequency: 3/7. (OMIM:300263)
- Thoracic kyphosis (HP:0002942): Over curvature of the thoracic region, leading to a round back or if sever to a hump. Evidence: TAS. (OMIM:300263)
- Synophrys (HP:0000664): Meeting of the medial eyebrows in the midline. Evidence: TAS. (OMIM:300263)
- Pes planus (HP:0001763): A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced. Evidence: TAS. Frequency: 1/7. (OMIM:300263)
- Prominent supraorbital ridges (HP:0000336): Greater than average forward and/or lateral protrusion of the supraorbital portion of the frontal bones. Evidence: TAS. (OMIM:300263)
- 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: 1/1. (PMID:17594395)
- Hypernasal speech (HP:0001611): A type of speech characterized by the presence of an abnormally increased nasal airflow during speech associated with structural abnormality of the nasal passages. Evidence: TAS. (OMIM:300263)
These phenotypes are associated with the disease syndromic X-linked intellectual disability Siderius type (OMIM:300263).