- Mild intellectual disability (HP:0001256, a Human Phenotype Ontology term): 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: 10/10. (PMID:15557513)
- Absent speech (HP:0001344, a Human Phenotype Ontology term): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 1/5. (PMID:28143899)
- Delayed ability to walk (HP:0031936, a Human Phenotype Ontology term): 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: 2/5. (PMID:28143899)
- Seizure (HP:0001250, a Human Phenotype Ontology term): 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: 4/5. (PMID:28143899)
- Global developmental delay (HP:0001263, a Human Phenotype Ontology term): 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. (PMID:28143899)
- Infantile onset (HP:0003593, a Human Phenotype Ontology term): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. (PMID:28143899)
- Autosomal recessive inheritance (HP:0000007, a Human Phenotype Ontology term): 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 individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:15557513)
- Self-injurious behavior (HP:0100716, a Human Phenotype Ontology term): Self-aggression. Evidence: PCS. Frequency: 5/5. (PMID:28143899)
- Attention deficit hyperactivity disorder (HP:0007018, a Human Phenotype Ontology term): Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient. Evidence: PCS. Frequency: 2/5. (PMID:28143899)
- Severe intellectual disability (HP:0010864, a Human Phenotype Ontology term): 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: 5/5. (PMID:28143899)
These phenotypes are associated with the disease intellectual disability, autosomal recessive 2 (OMIM:607417, an entry in Online Mendelian Inheritance in Man).