Developmental and epileptic encephalopathy-71 (DEE71) is characterized by early neonatal refractory seizures, respiratory failure, structural brain abnormalities and cerebral edema, with death within weeks after birth. Glutamine levels are significantly increased (z score 3.2-11.7). Three patients have been described (summary by Rumping et al., 2019).

Hereditary diffuse leukoencephalopathy with spheroids-2 (HDLS2) is an autosomal dominant neurodegenerative disorder characterized by progressive cognitive and executive dysfunction, psychiatric disturbances, and neurologic symptoms, such as gait abnormalities, paresis, seizures, and rigidity. Symptom onset is usually in adulthood, although earlier onset has been reported. Some patients have an acute encephalopathic course with severe neurologic decline resulting in early death, whereas other patients have a more protracted and chronic disease course. Neuropathologic examination shows a leukoencephalopathy with axonal spheroids and myelination defects (summary by Sundal et al., 2012). For a discussion of genetic heterogeneity of HDLS, see HDLS1 (221820).