Cerebellar dysfunction was also clinically observed in SPG7 variant carriers VALS125 (saccadic pursuit) with no correlating cerebellar atrophy on brain MRI at the time of investigation, TALS002-01 (ataxic gait) and MD018 (saccadic pursuit, nystagmus) with no available brain MRI. The gene discussed is SPG7; the disease is pathologic nystagmus.