SUCLA2 Arg407Trp mutation can cause a nonprogressive movement disorder – deafness syndrome

SUCLA2 is a component of mitochondrial succinate-CoA ligase and nucleotide diphosphokinase activities. Its absence results in Krebs cycle failure, mitochondrial DNA depletion, and a childhood-fatal encephalomyopathy. We describe a purely neurologic allelic form of the disease consisting of deafness, putamenal hyperintensity on MRI and a myoclonic-dystonic movement disorder unchanging from childhood into, so far, the late fourth decade. We show that succinate supplementation circumvents the Krebs cycle block, but does not correct the neurologic disease. Our patients’ Arg407Trp mutation has been reported in children with (yet) no MRI abnormalities. It remains possible that early succinate supplementation could impact the disease.