A novel homozygous variant in the SPG7 gene presenting with childhood optic nerve atrophy

Abstract

Purpose: To describe a case of hereditary spastic ataxia (HSP) presenting with childhood optic nerve atrophy and report a novel homozygous variant in the SPG7 gene.

Observations: A 57-year-old man suffering from progressive optic nerve atrophy since childhood eventually underwent genetic testing. A targeted whole exome gene sequencing panel for optic neuropathy identified a novel homozygous variant in the SPG7 gene, c.2T > G, p.(Met?), which likely abolished production of paraplegin, an inner mitochondrial membrane protein. Subsequent neurologic examination revealed subtle signs of spastic paraplegia and ataxia in keeping with the genetic diagnosis of SPG7.

Conclusion and importance: Spastic paraplegia 7 (SPG7) is an autosomal recessive form of the neurodegenerative disorder HSP. Pure HSP is characterized by spastic paraparesis in the lower limbs, whereas complicated HSP presents additional neurological manifestations. This case report adds to the evidence that SPG7 can present with childhood optic nerve atrophy, preceding the characteristic SPG7 manifestations. SPG7 should be considered in the workup of suspected hereditary optic neuropathy.

Keywords: Hereditary optic neuropathy; Hereditary spastic paraplegia; Optic nerve atrophy; SPG7 gene; Spastic paraplegia 7.