12 Hos patienter, som blev diagnosticeret under svangerskabet og behandlet, før der forekom anfald af hyperammonæmisk encefalopati, var overlevelsen 100%, men selv hos disse patienter viste de fleste i efterforløbet kognitiv svækkelse eller andre neurologiske defekter.
In patients diagnosed during gestation and treated prior to any episode of hyperammonaemic encephalopathy, survival was 100%, but even in these patients, many subsequently demonstrated cognitive impairment or other neurologic deficits.