Table 2.

Creatine Deficiency Disorders: Comparison of Phenotypes by Select Features

FeatureGAMT Deficiency 1AGAT Deficiency 2CRTR Deficiency 3
DD & cognitive dysfunction 4 ●●●●●●●●●
Speech-language disorder ●●●●●●
Seizure ●●●●●
Epilepsy ●●NR●●
Behavior problems ●●●●●
Muscle weakness /
Myopathy 		NR●●NR
Hypotonia ●●●●
Movement disorder ●NR●

●●● = all; ●● = common; ● = infrequent; AGAT = L-arginine:glycine amidinotransferase; CRTR = creatine transporter; DD = developmental delay; GAMT = guanidinoacetate methyltransferase; NR = not reported

1.
2.
3.
4.

Note that individuals diagnosed and treated from the newborn period or infancy with good treatment compliance may have normal developmental milestones, cognitive functions, and IQ.

From: Creatine Deficiency Disorders

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