Novel Homozygous Mutation of the AIMP1 Gene: A Milder Neuroimaging Phenotype With Preservation of the Deep White Matter

Abstract

Background: Mutations in AIMP1, which plays an important role in the development and maintenance of axon-cytoskeleton integrity and regulating neurofilaments, cause neurodegeneration of variable severity and white matter abnormalities. Methods: From the patient records we analyzed the clinical evaluation, molecular genetics, neurodiagnostic, and neuroradiological investigations. Results: We describe six members of a large consanguineous family with a phenotype of severe neurodegeneration in the form of developmental delays, progressive microcephaly, epilepsy, and failure to thrive. MRI showed callosal atrophy and T2 hyperintensity in the superficial white matter. The periventricular and deep white matter structures were, however, preserved. MR spectroscopy demonstrated N-acetylaspartate preservation without evidence of neuroinflammation. Exome sequencing showed a novel homozygous mutation of the AIMP1 gene in all individuals: c.917A>G (p.(Asp306Gly)). Conclusions: This novel homozygous mutation of the AIMP1 gene is characterized by preserved development of the periventricular and deep white matter structures as demonstrated by MRI and MR spectroscopy correlation.