Newborn Screening: Guanidinoacetate Methyltransferase Deficiency —Newborn Screening Panel Nomination

Wisconsin health care providers can nominate a condition to add to the Wisconsin newborn screening panel. The panel is part of the Wisconsin Newborn Screening program.

The purpose of this page is to show providers the nomination process for Guanidinoacetate methyltransferase (GAMT).

What is Guanidinoacetate methyltransferase (GAMT) deficiency?

Guanidinoacetate methyltransferase (GAMT) deficiency is one of three metabolic disorders related to cerebral creatine deficiency. It is an autosomal recessive disorder due to biallelic variants in the gene, GAMT, which encodes for the enzyme guanidinoacetate methyltransferase (OMIM #601240). This enzyme converts Guanidinoacetate (GUAC) to creatine and a deficiency in this enzyme leads to a build-up of GUAC and creatine deficiency. This disorder presents neurologic signs and symptoms including developmental delays particularly in speech, intellectual disability, behavioral issues including autism, seizures, and movement disorders like ataxia. Pre-symptomatic treatment with dietary interventions and creatine has shown significantly improved outcomes with most individuals being neurologically typical.

Nomination process for GAMT

The following timeline outlines the newborn screening panel nomination process:

• September 25, 2024—The Wisconsin Newborn Screening program received a nomination (PDF) to add GAMT to the newborn screening panel.
• October 18, 2024—The Wisconsin Newborn Screening Metabolic Subcommittee had a meeting where it considered the nomination. The subcommittee recommended adding GAMT to the Wisconsin newborn screening panel and forwarded this suggestion to the Wisconsin Newborn Screening Umbrella Committee.
• December 6, 2024—The Wisconsin Newborn Screening Umbrella Committee adopted the recommendation to add GAMT to the Newborn Screening Panel of conditions. They forwarded the recommendation to the Secretary’s Advisory Committee on Newborn Screening.
• March 14, 2025—The Secretary’s Advisory Committee on Newborn Screening considered the nomination and forwarded a report (PDF) to the Wisconsin Department of Health Services (DHS) Secretary in support of adding GAMT to the Newborn Screening Panel of conditions.
• February 17, 2026—The Secretary approved the recommendation (PDF) to add GAMT to the Newborn Screening Panel.

Learn more about administrative rulemaking at DHS and the Wisconsin Legislature. If you have questions about the nomination process, contact the Newborn Screening Program at DHSNewbornScreening@dhs.wisconsin.gov.