Evaluation of the METAglut1™ test in the diagnosis of glucose transporter type 1 deficiency syndrome - INAHTA Brief

Glucose transporter type 1 (Glut1) deficiency syndrome is an encephalopathy characterised, in its typical form, by treatment-resistant infantile-onset epilepsy, slowed head circumference growth resulting in microcephaly, delayed psychomotor development, spasticity, ataxia, dysarthria and other paroxysmal neurological disorders. “Atypical” forms, including a very broad variety of phenotypes, are also described. The prevalence of the condition is between 1/83,000 and 1/24,000.

The diagnosis of Glut1 deficiency syndrome is based on demonstration of hypoglycorrhachia as the reference test. This requires the performance of a lumbar puncture. An additional genetic test (molecular analysis of the SLC2A1 gene) can be used to confirm the diagnosis.

The METAglut1™ test is an in vitro diagnostic medical device (IVDMD). The test is performed on a blood sample to detect a reduction in glucose transporter (Glut1) expression on the surface of circulating erythrocytes and therefore diagnose glucose transporter type 1 deficiency syndrome.

In November 2017, METAFORA Biosystems SAS, the company that markets the METAglut1™ test, received the approval of the HAS to carry out a clinical study as part of the French “forfait innovation” innovation funding programme. The clinical study proposed in this context aimed to evaluate the diagnostic performance of the METAglut1™ test in patients with a clinical presentation compatible with glucose transporter type 1 deficiency syndrome, thereby providing the clinical data required for a procedure to be able to claim a sufficient expected clinical benefit.

With the clinical study now completed, the French Directorate General of Healthcare Provision (DGOS) therefore consulted the HAS on 29 April 2022, with a view to assessing whether it would be appropriate for this test to be funded by the French National Health Insurance system.

The objective of this work is to evaluate the diagnostic performance of the METAglut1™ test in comparison with glycorrhachia after lumbar puncture, in terms of sensitivity, specificity, positive predictive value and negative predictive value (NPV), in the diagnosis of glucose transporter type 1 deficiency syndrome, with a view to positioning the METAglut1™ test as a first-line test in place of glycorrhachia.