Patients with L-2-hydroxyglutaric aciduria have an increased risk of various brain tumors (ependymomas, primitive neuroectodermal tumors, low and high-grade gliomas, medulloblastomas, and oligodendrogliomas). It has not yet been possible to put an exact figure on the risk level.
Clinical L2HGA usually manifests within the first year of life with developmental delays, epileptic seizures, or coordination disorders. Around half of the patients have an above-average head circumference. Other symptoms are muscular weakness (usually during the early stage of the disease), movement pattern disorders, abnormal behavior, and spasticity (muscle cramps, tending to occur later on in the progression). Overall, the progression of the disease is slow, and most people affected reach adulthood. However, it may eventually lead to the complete loss of motor skills (e.g. loss of the ability to walk) and speech problems.
In laboratory chemical testing, L2HGA is characterized by high levels of L-2-hydroxyglutaric acid in the urine, blood, and spinal fluid.