A Hypomorphic PTPN23 Variant Presenting Optic Atrophy and Spasmus Nutans-Like Nystagmus Without Brain Structural Abnormality

Protein tyrosine phosphatase, non-receptor type 23 (PTPN23) is an important protein for the development of the nervous system. Mutations in the gene encoding this protein lead to a rare autosomal recessive disorder characterized by developmental delay, intellectual disability, and brain structural abnormalities. Although optic atrophy have been reported in more than half of reported cases, detailed description of ophthalmological findings is largely unknown.