Conclusions: 3-MCG impairs brain bioenergetics at the level of energy formation, transfer and utilization. It is presumed that these mechanisms may be involved in the pathophysiology of the neurological dysfunction that occurs in patients affected by 3-MCCD. An increased level of N-acetylaspartate found in the pattern of urinary organic acids is a diagnostic hallmark of neurodegenerative Canavan disease (CD). Established confirmatory tests are the determination of aspartoacylase (aminoacylase 2) activity in cultured fibroblasts and mutation analysis by sequencing the ASPA gene. The enzyme activity test is of special importance, if mutation analysis yields no sequence variation with a clear pathologic significance. So far, a skin biopsy has been a prerequisite for testing aspartoacylase activity.