AIMP1 deficiency presents as a cortical neurodegenerative disease with infantile onset.

We report the second family with AIMP1 deficiency, due to a homozygous truncating AIMP1 (g.107248613 C > T) mutation. This female showed early-onset developmental arrest, intractable epileptic spasms, microcephaly, and a rapid clinical course leading to premature death, associated with cerebral atrophy and myelin deficiency on brain MRI. Clinical and neuroimaging findings are consistent with a primary neuronal degenerative disorder, rather than with the previously reported Perlizaeus-Merzbacher-like phenotype. Given its critical role in neurofilament assembly 16, impaired myelin formation is due to neuronal/axonal dysfunction. We propose that AIMP1 deficiency be added to the differential diagnosis of infantile onset, progressive neurodegenerative disease.