A - 190 Neuropsychological Profile of an Adolescent with Primary Mitochondrial Disorder.

Abstract

This case describes a 16-year-old Hispanic male presenting with progressive brain atropy and upper motor neuron symptoms. He was diagnosed with a primary mitochondrial disorder (MT-TL1; variant m.3255G > A). Language and history produced difficulties in establishing onset. There is no literature describing the neuropsychological outcomes of this rare disorder. The patient spoke Spanish exclusively until 4. At 12, the patient had a CT after a fall noting ventriculomegaly without transependymal migration of fluid. MRIs, neurological examinations, and whole exome sequencing were ordered. An unknown neurodegenerative process was suspected. Parents felt cognitive changes started with the fall, but care team suspected onset as early as kindergarten due to reports of difficulty learning to read. Neuropsychological evaluation found IQ scores in the exceptionally low range, with relatively preserved adaptive skills. Significant fine motor and language deficits were noted, with low average to below average verbal memory, reading, and spelling, and exceptionally low visual memory and calculation. Executive functioning skills were variable. Extensive history-taking revealed that while the patient had struggled to learn to read English in kindergarten, he had taught himself to read in Spanish at home without difficulty concurrently. Although m.3255G > A mutation is the most frequent of MT-TL1 mutations, literature has only described its mutation associated with myopathy, maternal inherited diabetes and deafness, focal segmental glomerulosclerosis, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). No literature has defined neuropsychological outcomes of this rare disorder. Further, this case highlights the importance of understanding how language and education intersect in English Language Learner children.