What is Glut1 Deficiency?
Glucose Transporter Type 1 Deficiency Syndrome (Glut1 Deficiency or Glut1 DS for short) is a genetic neurometabolic disorder that impairs brain metabolism. Glucose isn’t transported across the blood-brain-barrier properly, creating an energy crisis that affects the brain’s ability to grow and function. When you eat any carbohydrate food, your body turns it into glucose in your blood. Glut1 is the cellular machine that moves that glucose from your blood into your brain. Someone with a Glut1 deficiency has a coding error on the part of their DNA that makes the Glut1 protein work properly, so their brains end up not getting enough glucose — causing a myriad of symptoms that range widely in severity among patients.
What causes Glut1 Deficiency?
Glut1 Deficiency is caused by a mutation in the SLC2A1 gene which regulates the “type 1” glucose transporter protein (Glut1). This is the main transporter of glucose across the blood-brain barrier. This disruption of glucose into the brain causes an assortment of symptoms that vary considerably from one patient to another. There are currently less than 1,000 patients diagnosed worldwide with Glut1 DS, but experts believe there are thousands in the U.S. alone who still need to be diagnosed. Early diagnosis is key, there is no cure, but there is an effective form of treatment: the Ketogenic Diet.
What Glut1 Deficiency is not:
Glut1 Deficiency is not a sensitivity, intolerance or allergy to gluten.
Most patients with Glut1 Deficiency are on the Ketogenic diet, which is a low-carb/high fat diet. So gluten is restricted because of its carbohydrate content, not because of any allergy to it.
How do you pronounce Glut1?
Glute one. Glute rhymes with flute.
Early warning signs of Glut1 Deficiency, for the non-seizure/movement disorder type:
See G1 Foundation for the complete list. I will only mention the ones that my Glut1 son, Drake, had experience with.
Ataxia: Having an abnormal gait, uncoordinated movements, staggering and unsteadiness. Similar to being tipsy from drinking alcohol.
Dyskinesia: Having involuntary muscle movements.
Paroxysmal Exercise Induced Dyskinesia (PED): Having sudden involuntary muscle movements induced by exercise. Paroxysmal means sudden or jerky.
Speech Disorder: Articulation at word level (difficult to understand especially when the context in unknown). Slurred speech while having an ataxia episode. Signs of receptive language communication disorder (problem with understanding/processing language tasks) and communication disorder (impedes ability to pair words with emotions). Speech Therapy can help with these problems.
Our speech therapist for Drake went above and beyond our expectations with not only helping his articulation, but also designing activities to help with his schoolwork, in particular story comprehension.
Fine & Gross Motor Problems: Problems with body spatial awareness and motor planning. Problems with balance and coordination. Problems with sequencing/performing tasks in order. Problems with fine motor planning, writing (control, placement and sizing of letters) and cutting with scissors. Occupational Therapy can help with these problems.
One way to think of ataxia is that both fluent speech and motor control are generated by the cerebellum part of the brain. Ataxia means impairment of the cerebellum. So ataxia can impact both speech and motor control.
Physical Problems: Having low muscle tone, weak muscles and poor endurance. Often foot orthotics/inserts are needed. Getting on the Ketogenic diet and then enough time and exercise to build up strength can help a lot. A physical therapist can help find the right exercises and make a plan to catch up.
Microcephaly: Born with a typical head circumference, but then can develop a small head circumference over time.
Heat sensitivity: Excessive sweating while exercising (even in air-conditioning) and conversely having trouble with getting too cold easily. Kids will find their own ways to regulate their body temperature, like wanting to be under warm blankets or in warm clothes. It may be wise to seek sports that are climate controlled, or in water.
What can I do for my mildly Glut1 Deficient kid?
First and foremost, the Ketogenic diet is critical for getting ketone energy into the brain. With brain glucose in short supply, due to the impaired transport system for it, the ketones are the only brain fuel that can make it from the blood into the brain. Giving the brain the energy it needs to function and grow well.
Also, it is good to try early intervention therapies, such as Occupational Therapy (OT), Physical Therapy (PT) and Speech Therapy. You don’t have to do them all at once! We had a time where therapy was our sport, but now we do a couple of months of therapy as needed with breaks in between.
Sports: Tae Kwon Do has been wonderful for us with its climate control and targeted movement guidance. Swimming, gymnastics, and equine therapy are all wonderful choices to get your kid moving.
Here are some things that Drake is good at that are common among other Glut1 Deficiency kids:
Good attention to tasks and activities, especially with a visual component. Good eye contact and joint attention. Good at socializing with peers. Fun loving and empathetic. Sweet dispositioned and hard-working when motivated. May use silliness as a way to avoid difficult tasks.
Drake can go the pace of a normal child, but has to work harder than his peers to achieve academic success.
Why do Ketones help Gult1 Deficiency Kids?
Eating a high fat, low carb diet will switch a person over to using their ketone energy system instead of their glucose energy system. Humans are designed to work well with either diet normally, but in a Glut1 Deficient kid, glucose can’t get into the brain properly without a fully functioning glucose transport system.
Luckily, ketones are an excellent brain fuel. Some studies are showing that ketones are better than glucose as a fuel for brains, even for non-Glut1 Deficient people. But for a Glut1 kid, ketones are critical!