Neuropsychologic profile of a high-functioning family with a mitochondrial cytopathy.

Objective: To examine the neuropsychologic profile of 3 family members diagnosed with the same mitochondrial cytopathy corresponding to a defect in the respiratory chain.

Background: The neuropsychologic functioning of patients with mitochondrial cytopathies has been largely unexamined in the literature. These mitochondrial defects often result in cell death and the failure of whole systems, including the brain. There are over 40 known types of mitochondrial cytopathies, which vary greatly in their genetic, clinical, and behavioral manifestations.

Method: The following project describes the neuropsychologic profiles of a family (a mother and her 2 children) afflicted by the same mitochondrial cytopathy possibly associated with nucleotide 15,924. Standardized tests of premorbid intelligence estimation, attention, executive function, language, verbal and visual memory, visuospatial functioning, motor functioning, visual acuity, mood, and activities of daily living were administered.

Results: Participants' profiles were characterized by estimated intellectual ability in the average to superior range with marked variability on a number of assessments, making it difficult to identify a distinct pattern. General trends, however, were reflective of executive function impairment associated with dysfunction of frontal-subcortical systems.

Conclusions: Mitochondrial disorders are extremely complicated and variable in their presentation. A multifactor approach should be adopted when examining neuropsychologic profiles.