Ataxia/movement disturbance developed in all patients (100%), which is consistent with the literature on atypical populations.12, , -15 Disease progression before treatment was slower compared with classic CLN2 disease (median annualized rate of ML score decline of 0.5 units/y vs 1.8 units/y in untreated patients).11 The gene discussed is TPP1; the disease is cerebellar ataxia.