Questions and answers to the Glut1 defect
Does the GLUT1 defect manifest in pregnancy?
GLUT1 deficiency syndrome is a genetic defect generated at the very start of life. Blood vessels, the blood-brain barrier, and the GLUT1 function develop as early as the 4-6th week of pregnancy.
Does the GLUT1 defect affect the development of the child during pregnancy?
Interestingly there is no evidence that the unborn child is affected by the GLUT1 defect. The reason is yet unknown – the glucose demand of the unborn baby is low. Possibly other glucose transporters help to compensate for the GLUT1 defect. Children with GLUT1 deficiency syndrome usually are normal at birth – seizures start when the glucose demand in brain increases within the first months of life.
Is GLUT1 deficiency syndrome always inherited?
No. Most mutations identified are heterozygous private mutations – the child carries a novel mutation that is not present in both parents. To date three families with inherited autosomal-dominant mutations transmitted within the family have been identified.
Can GLUT1 deficiency syndrome be identified in pregnancy?
The prenatal diagnosis of GLUT1 deficiency is not possible. In families carrying autosomal-dominant mutation in the GLUT1 gene this mutation in theory could be looked for in the unborn child, but it has never been done.
Why do children with GLUT1 deficiency syndrome develop significant language delay and such a complex movement disorder ?
We have not yet understood the effects the low glucose has in the brain of these children. Different brain areas have different glucose demands and interact in a very complex way. Brain cells show different vulnerability to hypoglycorrhachia and the distribution of glucose transporters throughout the brain is very heterogeneous.
What approaches are there to support the psychomotor development of GLUT1 deficient patients?
Patients with GLUT1 deficiency syndrome present as a very hetero-generous group. Based on a thorough assessment of the individual needs of the child a therapeutic programm, including physical and speech therapy, will be recommended; the success should be monitored closely during follow-ups in the outpatient department.
Can babies on the ketogenic diet be breastfed?
Breast milk contains relatively high amounts of fat, but is not ketogenic. Infants starting a ketogenic diet need to be weaned and will be fed with carbohydrate-free infant formula, fat emulsions and adequate supplements.