SLC2A1 and cerebellar ataxia: At its most severe, GLUT1 deficiency can present with early onset psychomotor delay, drug resistant epilepsy, acquired microcephaly and other signs of widespread neurological dysfunction, such as spasticity, ataxia, tremor, dystonia, choreoathetosis and ballism, which may all be paroxysmal, static or static with paroxysmal worsening.