Background: GDD is an underdiagnosed recessively inherited neurometabolic disorder, associated with encephalopathic crises and severe extrapyramidal symptoms. It is unknown, whether the severe neurological disease can be prevented by early diagnosis and therapy.

Subjects: 20 patients could be diagnosed before the onset of neurological disease.

Results: All children were treated with oral carnitine and an emergency regime during intercurrent illnesses. All children continue to develop normally up to report (mean age 6.1 years with a range from 8 months to 14.4 years).

Conclusions: In presymptomatic children with GDD, the onset of neurological disease can be prevented by vigorous treatment of catabolic crises during illnesses together with carnitine supplementation. The potential treatability of GDD is important for prenatal diagnosis and calls for increased attention to early presenting signs in order to recognize the disorder and to initiate treatment before the onset of irreversible neurological disease.