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SLC13A5 Deficiency

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About SLC13A5, a gene responsible for Citrate Transport

Citrate is a small molecule that is found in many types of food and throughout a person’s body. It is an important part of how a cell makes energy. The protein that moves citrate from outside a cell into the inner part of the cell is called a transporter.

In people with seizures, and neurologic problems related to functioning of the citrate transporter, there are changes in the amino acids that make up the transporter protein. The changes in the amino acids are likely to change the amount of citrate that is transported into the cell.

However, there are many unanswered questions in children with this disease that need to be addressed to identify appropriate treatment strategies:

  • Is there too much or too little citrate transport?
  • Why does too much or too little citrate transport cause a person to have seizures and other neurologic problems?
  • Are there specific drugs or supplements that might be tried to treat the disorder?

In order to answer these questions, it is critical to first have patients suffering from a citrate transporter problem appropriately diagnosed and made available for research studies.

Symptoms

Very few patients have been found with the disease so we are still learning what the full extent of the disease is and how we might be able to modify it with treatment. Below is a list of symptoms we have seen in children with the disorder:

  • Seizures beginning soon after birth
  • Persistent seizures of multiple types
  • Severe expressive language delay, with better receptive language
  • Hypotonia and ataxia
  • Episodes of body stiffening or weakness lasting a few minutes to a few hours
  • Brain MRI that appears normal

We are still trying to determine if the citrate levels in the children’s bodily fluid is abnormal.

Diagnosis

Currently, the only way to identify a citrate transporter problem as the cause of a child having intractable seizures is to look at the DNA sequence all of the genes in the human body and identify differences in the sequence of the SLC13A5 gene that might cause it to function abnormally. Hopefully soon there will be other and faster ways to make the diagnosis.

So far it appears that you need to have a change in the DNA sequence of both copies of the SLC13A5 genes. This means that you might inherit a copy with an abnormal sequence from both your mother and your father. Because mom and dad have a single copy of the gene that is abnormal, and they seem well, it appears that you only get the disease when you have two abnormal copies.

Treatments

At this time, there are no specific treatments that cure the disease. Treating seizures in children with citrate transporter disorder has proven difficult in some patients. We found that two patients have done slightly better with acetazolamide but would like to hear if anyone else has had any improvement with acetazolamide or if any other treatments have been helpful. We recommend that you speak with your neurologist about treatment options for your child.

Several children with SLC13A5 Deficiency are currently participating in a trial of Triheptanoin.