Deanna M Horst1, Lynne Ruess2, Jerome A Rusin3, Dennis W Bartholomew4. 1. Department of Radiology, Nationwide Children's Hospital, Columbus, Ohio. 2. Department of Radiology, Nationwide Children's Hospital, Columbus, Ohio; Department of Radiology, The Ohio State University College of Medicine and Public Health, Columbus, Ohio. Electronic address: lynne.ruess@nationwidechildrens.org. 3. Department of Radiology, Nationwide Children's Hospital, Columbus, Ohio; Department of Radiology, The Ohio State University College of Medicine and Public Health, Columbus, Ohio. 4. Center for Molecular and Human Genetics, Nationwide Children's Hospital Research Institute, Columbus, Ohio; Department of Pediatrics, The Ohio State University College of Medicine and Public Health, Columbus, Ohio.
Abstract
BACKGROUND: Nuclear polymerase gamma (POLG) mutations are the most common cause of inherited mitochondrial disease. POLG mutation diseases have a broad spectrum of clinical manifestations; the lethal infantile form is myocerebrohepatopathy spectrum. PATIENT: A 4-month-old boy was referred for poor feeding, emesis, failure to thrive, and hypotonia. RESULTS: Brain computed tomography was normal. Brain magnetic resonance imaging with and without contrast demonstrated bilateral enhancement of cranial nerves III, V-X, and the upper and midcervical nerve roots. Liver biopsy revealed early cirrhosis, steatosis, and focal necrosis. Muscle biopsy did not demonstrate specific abnormalities of mitochondrial morphology or number. Electron transport chain analysis of both fibroblasts and muscle demonstrated deficiencies. Because of suspected mitochondrial depletion disorder, testing was performed for mitochondrial abnormalities including analysis of the POLG gene, which revealed two pathogenic mutations, c.1399G>A (p.A467T) and c.3285C>G (p.S1095R). CONCLUSIONS: We report abnormal gadolinium enhancement of multiple cranial nerves and cervical nerve roots in an infant with myocerebrohepatopathy spectrum disease whose brain MRI otherwise revealed only mild atrophy. Mitochondrial disease should be included in the differential diagnosis of cranial nerve enhancement. Contrast-enhanced MRI aids in the diagnostic evaluation of infants with developmental delay and suspected neurological disease.
BACKGROUND: Nuclear polymerase gamma (POLG) mutations are the most common cause of inherited mitochondrial disease. POLG mutation diseases have a broad spectrum of clinical manifestations; the lethal infantile form is myocerebrohepatopathy spectrum. PATIENT: A 4-month-old boy was referred for poor feeding, emesis, failure to thrive, and hypotonia. RESULTS: Brain computed tomography was normal. Brain magnetic resonance imaging with and without contrast demonstrated bilateral enhancement of cranial nerves III, V-X, and the upper and midcervical nerve roots. Liver biopsy revealed early cirrhosis, steatosis, and focal necrosis. Muscle biopsy did not demonstrate specific abnormalities of mitochondrial morphology or number. Electron transport chain analysis of both fibroblasts and muscle demonstrated deficiencies. Because of suspected mitochondrial depletion disorder, testing was performed for mitochondrial abnormalities including analysis of the POLG gene, which revealed two pathogenic mutations, c.1399G>A (p.A467T) and c.3285C>G (p.S1095R). CONCLUSIONS: We report abnormal gadolinium enhancement of multiple cranial nerves and cervical nerve roots in an infant with myocerebrohepatopathy spectrum disease whose brain MRI otherwise revealed only mild atrophy. Mitochondrial disease should be included in the differential diagnosis of cranial nerve enhancement. Contrast-enhanced MRI aids in the diagnostic evaluation of infants with developmental delay and suspected neurological disease.