Usefulness of diagnostic tools in a GLUT1 deficiency syndrome patient with 2 inherited mutations

In some patients with GLUT1 deficiency syndrome (GLUT1-DS), the diagnosis can be difficult to reach. We report a child with 2 inherited mutations suggesting an autosomal recessive transmission of SLC2A1 mutations.

The child and her parents were explored with erythrocyte 3-O-methyl-d-Glucose uptake, glucose uptake in oocytes expressing GLUT1 with the gene mutations and measure of the expression of GLUT1 at the surface of the circulating red blood cells by flow cytometry (METAglut1™ test).

Both erythrocyte glucose uptake and glucose uptake in oocyte with the patient's mutations did not support the diagnosis of a mild GLUT1-DS phenotype with autosomal recessive transmission of SLC2A1 mutations. Instead, GLUT-1 expression at the surface of the erythrocytes appeared to better correlate with the clinical phenotypes in this family.

The diagnostic value of these functional/expression tools need to be further studied with a focus on mild phenotype of GLUT1-DS.