- Cerebellar vermis hypoplasia (HP:0001320): Underdevelopment of the vermis of cerebellum. Evidence: IEA. Frequency: 1/1. (OMIM:610992)
- Hypertonia (HP:0001276): A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move. Evidence: PCS. Frequency: 1/2. (PMID:17436247)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: PCS. Frequency: 1/2. (PMID:17436247)
- 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: TAS. Frequency: 1/2. (OMIM:610992)
- Decreased CSF serine concentration (HP:0500228): Abnormally decreased levels of serine in cerebrospinal fluid. Evidence: PCS. Frequency: 2/2. (PMID:17436247)
- 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: IEA. Frequency: 20/20. (OMIM:610992)
- Secondary microcephaly (HP:0005484): Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth. Evidence: IEA. (OMIM:610992)
- Hyposerinemia (HP:0012279): Reduced concentration of serine in the blood. Evidence: PCS. Frequency: 2/2. (PMID:17436247)
- Hypoglycinemia (HP:0012277): An abnormally reduced concentration of glycine in the blood. Evidence: PCS. Frequency: 2/2. (PMID:17436247)
- Cyanotic episode (HP:0200048). Evidence: PCS. Frequency: 1/2. (PMID:17436247)
- 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:17436247)
- Death in infancy (HP:0001522): Death within the first 24 months of life. Evidence: PCS. Frequency: 1/2. (PMID:17436247)
- 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: PCS. Frequency: 1/2. (PMID:17436247)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. Frequency: 1/2. (PMID:17436247)
- Neonatal onset (HP:0003623): Onset of signs or symptoms of disease within the first 28 days of life. Evidence: PCS. Frequency: 2/2. (PMID:17436247)
- Decreased CSF glycine concentration (HP:0034390): Abnormally decreased levels of glycine in cerebrospinal fluid. Evidence: PCS. Frequency: 2/2. (PMID:17436247)
These phenotypes are associated with the disease PSAT deficiency (OMIM:610992).