Response

Sir,

We thank Dr. Castro-Gago and his group [1] for their comments on our paper [2]. Their data emphasize the importance of considering mitochondrial disorders in children with a variety of epileptic encephalopathies, as also supported by Lee et al. [3]. All three series showed that almost half of the patients had West and/or Lennox Gastaut syndromes. Generalized epilepsies were more frequently seen in the series of Castro Gago et al. [1] and Lee et al. [3], whereas partial epilepsy was more frequently diagnosed in our patients [2].

The experience of the three groups of researchers [1] [2] [3] suggests a possible relationship between mitochondrial oxidative stress dysfunction and the epileptogenic process. A review of the data indicates that such a relationship may vary according to ethnicity and genetic background, as the most frequent respiratory chain defect was complex I in South Korea [3], complex II in the United States [2] and complex IV in Spain [1].

These studies emphasize the need for further prospective investigations in this evolving field.

D. S. Khurana, L. Salganicoff, J. J. Melvin, E. F. Hobdell, I. Valencia, H. H. Hardison, H. G. Marks, W. D. Grover , A. Legido

References

• 1 Castro-Gago M, Blanco-Barca O, Campos-Gonzalez Y. et al . Epidemiology of pediatric mitochondrial respiratory chain disorders in northwest Spain.  Pediatr Neurol. 2006;  34 204-211
• 2 Khurana DS, Salganicoff L, Melvin JJ. et al . Epilepsy and respiratory chain defects in children with mitochondrial encephalopathies.  Neuropediatrics. 2008;  39 8-13
• 3 Lee YM, Kang HC, Lee JS. et al . Mitochondrial respiratory chain defects: underlying etiology in various epileptic conditions.  Epilepsia. 2008;  49 685-690

Correspondence