Giant axonal neuropathy: a rare inherited neuropathy with a novel mutation.

Abstract

We present a 7.5-year-old boy born to a family from the Iranian Azeri Turkish ethnic group with a consanguineous marriage who presents with a unique set of symptoms, suggesting Giant Axonal Neuropathy. He achieved independent walking at age 3 years, with frequent falling during running. Physical and neurological examinations reveal curly blond hair, generalized muscle atrophy, slow speech and difficulty swallowing solid food, foot drop, pes cavus, hammertoe deformities; reduced deep tendon reflexes, clumsy gait, impaired sense of position, and intention tremors.This comprehensive report significantly expands the clinical and mutational spectrum of Giant Axonal Neuropathy. Whole Exome Sequencing (WES) analysis revealed a novel homozygous variant (NC_000016.10(NM_022041.3):c.2T > C) in the GAN gene, confirmed by Sanger sequencing. Segregation analysis showed that the parents were heterozygous for the variant. The variant was absent in a cohort of 430 healthy individuals from the same ethnic group and in other published population databases such as GenomAD and the 1000 Genome. The clinical manifestations, segregation analysis, population study, and bioinformatics analysis collectively confirm the pathogenicity of variant.