GAMT

The GAMT gene provides instructions for making the enzyme guanidinoacetate methyltransferase, which is active in the liver, pancreas, and kidneys. This enzyme participates in the two-step synthesis of the compound creatine from the protein building blocks (amino acids) glycine, arginine, and methionine. Specifically, guanidinoacetate methyltransferase controls the second step of the sequence, in which creatine is produced from another compound called guanidinoacetate. Creatine is needed for many tissues in the body to store and use energy properly. It is involved in providing energy for muscle contraction, and is also important in nervous system functioning.

guanidinoacetate methyltransferase deficiency - caused by mutations in the GAMT gene

Fifteen mutations have been reported in the GAMT gene. Most affected individuals of Portuguese ancestry have a particular mutation in which the amino acid tryptophan is replaced by the amino acid serine at position 20 (written as Trp20Ser or W20S).

GAMT gene mutations impair the ability of the guanidinoacetate methyltransferase enzyme to participate in creatine synthesis. The effects of guanidinoacetate methyltransferase deficiency are most severe in organs and tissues that require large amounts of energy, such as the brain and muscles.