Should autistic children be evaluated for mitochondrial disorders?

Autism is etiologically heterogeneous; medical conditions are implicated in only a minority of cases, whereas metabolic disorders are even less common. Recently, there have been articles describing the association of autism with mitochondrial abnormalities. We critically review the current literature and conclude that mitochondrial disorders are probably a rare and insignificant cause of pure autism; however, evidence is accumulating that both autosomal recessive and maternally inherited mitochondrial disorders can present with autistic features. Most patients will present with multisystem abnormalities associated with autistic behavior. Finding biochemical or structural mitochondrial abnormalities in an autistic child does not necessarily imply a primary mitochondrial disorder but can also be secondary to technical inaccuracies or another genetic disorder. Clinicians should be careful in diagnosing a mitochondrial disorder in an autistic child because it has important implications for accurate genetic counseling, prognosis, and therapy.