Table 1.
Point mutations in human creatine transporter 1 (CRT-1) with the consequent CTD phenotypes.
| Variant | Clinical phenotype | References |
|---|---|---|
| P31L | Seizures, speech and motor delay, and thalamus atrophy | Rostami et al. (2020) |
| G87R | Intellectual disability | Rosenberg et al. (2004) |
| G132V | Intellectual disability | Lion-François et al. (2006) |
| R207W | Global developmental delays, hypotonia, intellectual disability, and language apraxia | Ardon et al. (2016) |
| G253R | Mild intellectual disability and language delay | Battini et al. (2011) |
| N331K | Speech delay, seizures, and hyperactivity | Mencarelli et al. (2011) |
| C337W | Intellectual disability | Rosenberg et al. (2004) |
| G356V | Epilepsy and mild intellectual disability | Mercimek-Mahmutoglu et al. (2009) |
| G381R | Intellectual disability, seizures, speech, and behavioral disturbance, hypotonia, and gastrointestinal problems | Hahn et al. (2002) |
| P382L | Severe intellectual disability, speech delay, behavioral problems, and epilepsy | Mercimek-Mahmutoglu et al. (2009) |
| P390L | Intellectual disability, learning difficulties, seizures, hyperactive and impulsive behavior | Rosenberg et al. (2004) and Heussinger et al. (2017) |
| R391W | Seizures, hyperactivity, aggressiveness, and hyperphagia | Mencarelli et al. (2011) |
| T394K | Intellectual disabilities, severe developmental delay and speech impairment, seizures, and mild scale autism | Wang et al. (2018) |
| A404P | Mild psychomotor retardation and language impairments | Alcaide et al. (2010) |
| G424D | Speech and language delay, learning difficulties, mild autistic features, social anxiety and attention deficit, aggressiveness, impulsiveness, and hyperactivity | Puusepp et al. (2010) |
| G466R | Developmental delay, dystonia, no speech, and epilepsy | Alcaide et al. (2011) |
| D474G | Mild intellectual disability and occasional febrile seizures | Bruun et al. (2018) |
| C491W | Generalized tonic-clonic seizures | Lion-François et al. (2006) |
| M510K | Moderate intellectual disability, antiepileptic drug-responsive seizures, hypotonia, and dysarthria | Bruun et al. (2018) |
| P544L | Moderate intellectual disability, generalized hypotonia, delayed language, and speech skills, and multifocal epileptic waves | Mancini et al. (2005) |
| P554L | Intellectual disability, hypotonia, intellectual disability, severe speech delay, seizures, autism, and epilepsy | Rosenberg et al. (2004) and Nozaki et al. (2015) |
| G561A | Intellectual disability | Kato et al. (2014) |
| F315del | Intellectual disability, epilepsy, autism, and speech delay | Fons et al. (2009) |
| N336del | Intellectual disability, seizures, and motor dyspraxia | Battini et al. (2007) |
| I347del | Moderate intellectual disability, aggressive behavior, and seizures | Clark et al. (2006) |
| F354del | Intellectual disability | Betsalel et al. (2008) |
| F360del | Intellectual disability, epilepsy, autism, and speech delay | Fons et al. (2009) and Sempere et al. (2009) |
| F408del | Intellectual disability, epilepsy, autism, seizure, speech and language delay and a reduced interest in the surroundings | Bizzi et al. (2002) and Póo-Argüelles et al. (2006) |
Only those CTD variants with identified clinical symptoms are listed, according to the reports available in the literature to date.