- Bruxism (HP:0003763): Bruxism is characterized by the grinding of the teeth including the clenching of the jaw and typically occur during sleep. Evidence: IEA. Frequency: 1/1. (OMIM:617903)
- Hyperventilation (HP:0002883): Hyperventilation refers to an increased pulmonary ventilation rate that is faster than necessary for the exchange of gases. Hyperventilation can result from increased frequency of breathing, an increased tidal volume, or both, and leads to an excess intake of oxygen and the blowing off of carbon dioxide. Evidence: IEA. Frequency: 1/1. (OMIM:617903)
- Inappropriate crying (HP:0030215): Uncontrolled episodes of crying occur without any apparent motivating stimuli. Evidence: PCS. Frequency: 1/1. (PMID:26740508)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: IEA. (OMIM:617903)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 1/1. (PMID:26740508)
- Short foot (HP:0001773): A measured foot length that is more than 2 SD below the mean for a newborn of 27 - 41 weeks gestation, or foot that is less than the 3rd centile for individuals from birth to 16 years of age (objective). Alternatively, a foot that appears disproportionately short (subjective). Evidence: IEA. Frequency: 1/1. (OMIM:617903)
- Sleep-wake cycle disturbance (HP:0006979): Any abnormality of an individual's circadian rhythm that affects the timing of sleeping and being awake is referred to as a sleep-wake disorder. Evidence: PCS. Frequency: 1/1. (PMID:26740508)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: IEA. Frequency: 1/1. (OMIM:617903)
- Dystonia (HP:0001332): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: IEA. (OMIM:617903)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: IEA. (OMIM:617903)
- 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: IEA. Frequency: 0/1. (OMIM:617903)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 1/1. (PMID:26740508)
- 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: 1/1. (PMID:26740508)
- Recurrent hand flapping (HP:0100023): A type of repetitive behavior in which the affected individual repeatedly waves the hands and/or arms rhythmically. Evidence: PCS. Frequency: 1/1. (PMID:26740508)
- Developmental stagnation (HP:0007281): A cessation of the development of a child in the areas of motor skills, speech and language, cognitive skills, and social and/or emotional skills. Evidence: PCS. Frequency: 1/1. (PMID:26740508)
- Abnormal autonomic nervous system physiology (HP:0012332): A functional abnormality of the autonomic nervous system. Evidence: IEA. (OMIM:617903)
- 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: 1/1. (PMID:26740508)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: IEA. (OMIM:617903)
- 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: IEA. (OMIM:617903)
- Small hand (HP:0200055): Disproportionately small hand. Evidence: IEA. (OMIM:617903)
- Macrocephaly (HP:0000256): Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium. Evidence: IEA. (OMIM:617903)
- Apnea (HP:0002104): Lack of breathing with no movement of the respiratory muscles and no exchange of air in the lungs. This term refers to a disposition to have recurrent episodes of apnea rather than to a single event. Evidence: IEA. (OMIM:617903)
- 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:26740508)
- 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:617903)
These phenotypes are associated with the disease neurodevelopmental disorder with poor language and loss of hand skills (OMIM:617903).