In ALS, there are decreased levels of excitatory amino acid transporter 2 (EAAT2), which is the main transporter that removes glutamate from the synapse; this leads to increased synaptic glutamate levels and excitotoxicity. Riluzole, a drug that modestly prolongs survival in ALS, inhibits glutamate release from pre-synaptic neurons; however, it is unclear if this mechanism is responsible for its therapeutic effect. Diagnosis
No test can provide a definite diagnosis of ALS, although the presence of upper and lower motor neuron signs in a single limb is strongly suggestive. Instead, the diagnosis of ALS is primarily based on the symptoms and signs the physician observes in the person and a series of tests to rule out other diseases. Physicians obtain the persons full medical history and usually conduct a neurologic examination at regular intervals to assess whether symptoms such as muscle weakness, atrophy of muscles, hyperreflexia, and spasticity are worsening. A number of biomarkers are being studied for the condition, but so far are not in general medical use. Diagnostic criteria
The diagnosis of ALS is based on the El Escorial Revised criteria and the Awaji criteria. The original El Escorial criteria had four levels of diagnostic certainty, based on how many of the four spinal cord regions were involved: bulbar, cervical, thoracic, and lumbar.
None of the glycogenoses are currently detected by standard or extended newborn screening. The disease is more common in people of Ashkenazi Jewish, Mexican, Chinese, and Japanese descent. References
Further reading
GeneReview/NIH/UW entry on Glycogen Storage Disease Type I

External links
 Media related to Glycogen storage disease type I at Wikimedia Commons