- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 2/6. (PMID:24699222)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 2/6. (PMID:24699222)
- 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: 6/6. (PMID:24699222)
- 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: PCS. Frequency: 5/6. (PMID:24699222)
- 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: 6/6. (PMID:24699222)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 2/6. (PMID:24699222)
- Early young adult onset (HP:0025708): Onset of disease at an age of greater than or equal to 16 to under 19 years. Evidence: PCS. Frequency: 1/6. (PMID:24699222)
- Hypomagnesemia (HP:0002917): The concentration of magnesium in the blood circulation is below the lower limit of normal. Evidence: PCS. Frequency: 6/6. (PMID:24699222)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 1/6. (PMID:24699222)
- Open operculum (HP:0100954): Underdevelopment of the operculum. Evidence: PCS. Frequency: 1/6. (PMID:24699222)
- Autosomal recessive inheritance (HP:0000007): 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:24699222)
- Class III obesity (HP:0025501): Obesity with a body mass index of 40 kg per square meter or higher. Evidence: PCS. Frequency: 2/5. (PMID:24699222)
- 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: 6/6. (PMID:24699222)
- 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:24699222)
These phenotypes are associated with the disease hypomagnesemia, seizures, and intellectual disability 1 (OMIM:616418).