The cause of SLC1A4 syndrome (also know as ASCT1 deficiency) is known, but not well-understood. 

The genetic defect involves a “gene” called SLC1A4 which is responsible for instructing the body to produce the ASCT1 protein.  Patients having such syndrome, the SLC1A4 is damaged (or “mutated”) and the ASCT1 is either no longer made or has low efficiency. 

While we do not fully understand what the function of the ACT1 protein, we do know that is mainly located in human brain cells.  

The ASCT1 transporter allows certain amino acids to get into the brain cells, and defects in SLC1A4 prevent these essential molecules from getting into the brain cells to do their job and make the brain work. 

SLC1A4 syndrome is a genetic condition that occurs when a change or mutation in DNA is inherited from both parents in an autosomal recessive manner, which means that both copies of the SLC1A4 gene in each cell have the mutation. If both parents carry a SLC1A4 mutation, there is a 25% chance of having a child with SLC1A4 deficiency every time they have a child.

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The most common mutation is the Glu256Lys (E256K) mutation with about 1 in 144 (0.7%) individuals of Ashkenazi-Jewish ancestry carry the mutation.

What Are The Symptoms Associated With SLC1A4 Syndrome

SLC1A4 syndrome is associated with :

  • Microcephaly (small head size)
  • Developmental delays.
  • Severe intellectual disability
  • Spasticity
  • Thin corpus callosum
  • Demyelination