- Decreased circulating guanidinoacetic acid concentration (HP:6001352): The concentration of guanidinoacetic acid in the blood circulation is below the lower limit of normal. Evidence: PCS. Frequency: 1/2. (PMID:11555793)
- Reduced tissue arginine:glycine amidinotransferase activity (HP:6000572): Activity of L-arginine:glycine amidinotransferase (GATM; EC 2.1.4.1) in the tissues below the lower limit of normal. GATM activity can be measured in multiple tissues including leukocytes and cultured fibroblasts. Evidence: PCS. Frequency: 1/1. (PMID:22386973)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 2/2. (PMID:11555793)
- 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:612718)
- Delayed ability to walk (HP:0031936): 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: 2/2. (PMID:11555793)
- Organic aciduria (HP:0001992): Excretion of non-amino organic acids in urine. Evidence: TAS. (OMIM:612718)
- 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: TAS. (OMIM:612718)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 2/2. (PMID:11555793)
- Gowers sign (HP:0003391): A phenomenon whereby patients are not able to stand up without the use of the hands owing to weakness of the proximal muscles of the lower limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:612718)
- Decreased urinary creatine level (HP:6000748): The amount of creatine in the urine, normalized for urine concentration, is below the lower limit of normal. Evidence: PCS. (PMID:20301745)
- Decreased urine guanidinoacetic acid level (HP:0034888): The concentration of guanidinoacetic acid in the urine, normalized for urine concentration, is below the lower limit of normal. Evidence: PCS. Frequency: 2/2. (PMID:11555793)
- Reduced brain creatine level by MRS (HP:0025051): A decrease in the level of creatine in the brain identified by magnetic resonance spectroscopy (MRS). Evidence: PCS. Frequency: 12/12. (PMID:11555793;PMID:20682460)
- Abnormal circulating creatinine concentration (HP:0012100): An abnormal concentration of creatinine in the blood. Evidence: PCS. Frequency: 0/2. (PMID:11555793)
- Simple febrile seizure (HP:0011171): A short generalized seizure, of a duration of <15 min, not recurring within 24 h, occurring during a febrile episode not caused by an acute disease of the nervous system intracranial infection or severe metabolic disturbance. Evidence: PCS. Frequency: 1/2. (PMID:11555793)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: TAS. (OMIM:612718)
- Autism (HP:0000717): Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV). Evidence: TAS. (OMIM:612718)
- 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:11555793)
- 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: 2/2. (PMID:11555793)
These phenotypes are associated with the disease AGAT deficiency (OMIM:612718).