Heterogeneity of axonal pathology in Chinese patients with giant axonal neuropathy

Giant axonal neuropathy (GAN) is a rare autosomal recessive neurodegenerative disorder caused by mutations in the GAN gene. Herein we report ultrastructural changes in Chinese patients with GAN.

General clinical assessment, sural nerve biopsy, and genetic analysis were performed.

Sural biopsy revealed giant axons in 3 patients, 2 with a mild phenotype and 1 with a classical phenotype. Ultrastructurally, all patients had giant axons filled with closely packed neurofilaments. In addition, the classical patient had some axons containing irregular tubular-like structures. GAN mutation analysis revealed novel compound heterozygous c.98A>C and c.158C>T mutations in the BTB domain in 1 mild patient, a novel homozygous c.371T>G mutation in the BACK domain in another mild patient, and a novel c.1342G>T homozygous mutation in the Kelch domain in the classical patient.

Closely packed neurofilaments in giant axons are common pathological changes in Chinese patients with GAN, whereas irregular tubular-like structures appear in the classical type of this neuropathy.