see  also Deficit of the synthesis of creatine and Creatine transporter deficiency

Prevalence: < 1/106. Creatine is an essential part of muscle and brain tissue: it is source of energy (phosphates exchange with ATP) and has neuromodulator properties by regulating the expression of post-synaptic GABA receptors . It could also have a protective effect against the consequences of cerebral anoxia and ischemia. It is either of alimentary origin (50%) or endogenous (liver, kidney, pancreas, some glial cells). It is eliminated by non-enzymatic cyclization as urinary creatinine. It is estimated that approximately 1.7 % of the total pool of body creatine is eliminated each day as urinary creatinine.

Cerebral creatine deficiency may be due to deficit of synthesis or to a deficit of intracerebral transport (see diagram)

Updated: September 2019