Three metabolic defects are known: two affect synthesis – guanidinoacetate metiltransferase (GAMT) and glycine amidinotransferase (AGAT) deficiencies– and one affect the Cr transporter (CRTR). We present the first three Spanish patients with GAMT deficiency, and we compare their clinical phenotype and treatment response with other published cases. Patients and method
The three patients presented mental retardation, epilepsy and autistic behaviour.
Cerebral creatine deficiency: First Spanish patients harbouring mutations in GAMT gene
 
  Keywords
 
 
  
   Creatine deficiency
  
 
 
  
   Epilepsy
  
 
 
  
   Guanidinoacetate methyltransferase
  
 
 
  
   Magnetic resonance spectroscopy
  
 
 
  
   Mental retardation
  
 
Abstract
 Background and objetive
Brain creatine (Cr) deficiencies are a group of inborn errors of metabolism that are characterized by an absence or severe reduction of brain Cr.
Clinically, these patients can display <dis>psychomotor/mental retardation</dis> and <dis>language disorders</dis>, commonly associated with epilepsy or <dis>movement disorders</dis>.
Three metabolic defects are known: two affect synthesis – guanidinoacetate metiltransferase (GAMT) and glycine amidinotransferase (AGAT) deficiencies– and one affect the Cr transporter (CRTR).
We present the first three Spanish patients with GAMT deficiency, and we compare their clinical phenotype and treatment response with other published cases.
Patients and method
The three patients presented <dis>mental retardation</dis>, epilepsy and <dis>autistic behaviour</dis>.
Patient 1 also had severe chorea.
Diagnosis was done by biochemical and genetic procedures (guanidinoacetate quantification, determination of GAMT activity and mutation analysis in the GAMT gene).
Results
An increase of guanidinoacetate was detected in urine and plasma.
Brain magnetic resonance spectroscopy revealed low Cr levels.
Enzymatic studies revealed a decreased GAMT activity in fibroblasts.
Molecular analysis detected pathogenic mutations in the GAMT gene.
After the deficiency was confirmed, the patients started treatment with Cr.
In addition, patient 2 and 3 received an arginine-restricted diet and ornithine supplements.
All them showed a partial improvement.
Conclusions
Patients with GAMT deficiency have an unspecific but relatively constant clinical presentation.
Brain Cr deficiency should be considered in patients with <dis>mental retardation</dis> of unknown aetiology, specially in those with <dis>movement disorders</dis> or epilepsy.
Early diagnosis is important in cases with known treatment such as GAMT deficiency.
Abstract
 Background and objetive
Brain creatine (Cr) deficiencies are a group of inborn errors of metabolism that are characterized by an absence or severe reduction of brain Cr.
Clinically, these patients can display psychomotor/mental retardation and language disorders, commonly associated with epilepsy or movement disorders.
Three metabolic defects are known: two affect synthesis – guanidinoacetate metiltransferase (GAMT) and glycine amidinotransferase (AGAT) deficiencies– and one affect the Cr transporter (CRTR).
We present the first three Spanish patients with GAMT deficiency, and we compare their clinical phenotype and treatment response with other published cases.
Patients and method
The three patients presented mental retardation, epilepsy and autistic behaviour.
Patient 1 also had severe chorea.
Diagnosis was done by biochemical and genetic procedures (guanidinoacetate quantification, determination of GAMT activity and mutation analysis in the GAMT gene).
Results
An increase of guanidinoacetate was detected in urine and plasma.
Brain magnetic resonance spectroscopy revealed low Cr levels.
Enzymatic studies revealed a decreased GAMT activity in fibroblasts.
Molecular analysis detected pathogenic mutations in the GAMT gene.
After the deficiency was confirmed, the patients started treatment with Cr.
In addition, patient 2 and 3 received an arginine-restricted diet and ornithine supplements.
All them showed a partial improvement.
Conclusions
Patients with GAMT deficiency have an unspecific but relatively constant clinical presentation.
Brain Cr deficiency should be considered in patients with mental retardation of unknown aetiology, specially in those with movement disorders or epilepsy.
Early diagnosis is important in cases with known treatment such as GAMT deficiency.
Three metabolic defects are known: two affect synthesis – guanidinoacetate metiltransferase (GAMT) and glycine amidinotransferase (AGAT) deficiencies– and one affect the Cr transporter (CRTR). We present the first three Spanish patients with GAMT deficiency, and we compare their clinical phenotype and treatment response with other published cases. Patients and method
The three patients presented <dis>mental retardation</dis>, epilepsy and <dis>autistic behaviour</dis>.
mental retardation
DISABILITY
autistic behaviour
DISABILITY