Gait disturbance in a patient with de novo 1.0-kb SOX2 microdeletion.

Abstract Background Sex-determining region Y-box 2 (SOX2) plays an important role in the early embryogenesis of the eye, forebrain, and hypothalamic–pituitary axis. Anophthalmia, microphthalmia, and hormonal abnormalities are commonly observed in patients with SOX2-related disorders. Although gait disturbance, particularly ataxic gait, has recently been observed in several cases, detailed data regarding the clinical course of gait disturbance in SOX2-related disorders are limited. Case report A 9-year-old Japanese boy presented with focal dyskinesia only during walking and running after he started walking at the age of 3 years. He also exhibited intellectual disability and mild dysmorphic features, including microcephaly, micropenis, and short stature associated with hormonal abnormalities. Gait disturbance with involuntary extremity movements only during walking and running was indicative of choreoathetosis and dystonia. Genetic analysis detected a de novo heterozygous 1.0-kb deletion including SOX2 at 3q26.32, as described in a previous technical paper. Conclusions SOX2-related disorders should be considered in patients with some anomalies having a differential diagnosis of dyskinesia. Focal dyskinesia only during walking and running may be a characteristic feature of SOX2-related disorders.