Affiliations: Division of Pediatric Neurology, Arkansas Children's
Hospital Research Institute, Little Rock, AR, USA
Note: [] Corresponding author: Richard E. Frye, Ph.D., Arkansas
Children's Hospital Research Institute, Slot 512-41B, 13 Children's Way, Little
Rock, AR 72202, USA. Tel.: +1 501 364 4662; Fax: +1 501 364 1648; E-mail:
[email protected]
Abstract: The recent scientific literature has documented an association
between autism and mitochondrial dysfunction, yet the majority of reported
cases of individuals with autism and mitochondrial disease have not reported a
specific genetic defect to explain the cause of the mitochondrial dysfunction.
Here we report two boys with regressive-type autism with similar biochemical,
electron microscopy and electron transport chain abnormalities consistent with
a mitochondrial disorder. Both boys manifested rare mutations in evolutionarily
conserved regions of the cytochrome b gene, a gene that codes for an important
component of complex III – one of the essential electron transport chain
complexes. Only one of these mutations has been previously reported, making
these mutations novel. Electron transport chain studies in two boys within this
report are consistent with dysfunction of the electron transport chain beyond a
complex III defect, consistent with other reports describing the effects of
cytochrome b gene mutations. This report expands the knowledge of the etiology
of mitochondrial dysfunction in children with autism.
Keywords: Autism, cytochrome B, complex III, mitochondrial dysfunction, mitochondrial DNA mutation, regression
