NCC Knowledge Nugget Series: GAMT ACT Sheet-GAMT ACT Sheet

GAMT ACT Sheet

Pdf Summary

Guanidinoacetate methyltransferase (GAMT) deficiency is an autosomal recessive condition that impairs the ability to synthesize creatine. Without creatine, the body is unable to use and store energy, leading to symptoms such as seizures, developmental delay, impaired speech development, behavioral changes, hypotonia, and movement disorders. The condition typically presents between 3 months and 3 years of age.<br /><br />To address this condition:<br />- Inform the family of the newborn screening result and ascertain the clinical status of the newborn.<br />- Consult with a pediatric metabolic specialist.<br />- Evaluate the newborn, even if asymptomatic.<br />- Initiate confirmatory/diagnostic testing and management as recommended by the specialist.<br />- Provide the family with basic information about GAMT deficiency and its management.<br />- Report the final diagnostic outcome to the newborn screening program.<br /><br />Diagnostic evaluation involves measuring guanidinoacetate, creatine, and creatinine levels in urine and plasma. Molecular genetic testing may also be required for confirmation.<br /><br />Treatment aims to promote normal growth and development by restoring creatine levels and reducing guanidinoacetate concentrations. This is accomplished through creatine supplementation and dietary therapy, which should be administered under the guidance of a metabolic specialist. Protein restriction, ornithine, and benzoate supplementation may be utilized.<br /><br />Additional information and resources can be found through the provided links, including information on newborn screening results communication, Gene Reviews, GARD, Medline Plus, the HRSA Newborn Screening Clearinghouse, and referral options such as the Find a Genetics Clinic Directory and Genetic Testing Registry.

Keywords

GAMT deficiency

Creatine synthesis impairment

Seizures

Developmental delay

Behavioral changes

Hypotonia

Movement disorders

Newborn screening

Diagnostic testing

Creatine supplementation