Nowadays, no curative treatment is available for GLYT1 encephalopathy, and disease management is exclusively supportive. Several treatments commonly used for nonketotic hyperglycinemia (another form of glycine encephalopathy) have been used in patients with GLYT1 encephalopathy, but none of them has been effective in mitigating the manifestations of the disorder. Most patients die in infancy.
A multidisciplinary management is recommended to manage psychomotor development, respiratory function, nutritional status and feeding, musculoskeletal malformations, and visual and hearing impairments if present. Thus, the patient should be evaluated by neonatologists, pediatric neurologists, nutritionists, traumatologists, physical medicine and palliative care specialists.
It is important to perform a neurologic assessment including electroencephalogram to distinguish startle responses from seizures. Brain imaging and physiologic tests, such as visual evoked potentials, brain stem evoked response audiometry, and evaluation of motor and sensory nerves, are recommended to better understand the extent of the clinical involvement.
There are no known agents to avoid. However, valproate (which is contraindicated in nonketotic hyperglycinemia) should be avoided as it increases the concentration of blood and cerebrospinal glycine.
On the other hand, parents of children affected by GLYT1 encephalopathy should receive genetic counselling. The risk of recurrence in these families is high, hence the possibility of prenatal or preimplantation genetic diagnosis should be discussed with the couples.
SLC6A9