An Extension Study to Evaluate the Long-Term Efficacy and Safety of BMN 190 in Patients With CLN2 Disease

Inclusion Criteria: * Must have completed 48 weeks in Study 190-201. * Is willing and able to provide written, signed informed consent. Or, in the case of patients under the age of 18 (or other age as defined by regional law or regulation), provide written assent (if required) and have written informed consent, signed by a legally authorized representative, after the nature of the study has been explained, and prior to performance of research-related procedures. * Males and females who are of reproductive age should practice true abstinence, defined as no sexual activity, during the study and for 6 months after the study has been completed (or withdrawal from the study). If sexually active and not practicing true abstinence, males and females of reproductive age must use a highly effective method of contraception while participating in the study. * If female, of childbearing potential, must have a negative pregnancy test at the Screening Visit and be willing to have additional pregnancy tests done during the study. Exclusion Criteria: * Has had a loss of 3 or more points in the combined motor and language components of the Hamburg CLN2 rating scale between Baseline of Study 190-201 and the Study Completion visit in Study 190-201 and would not benefit from enrolling in the study in the Investigator's discretion. * Has a score of 0 points on the combined motor and language components of the Hamburg CLN2 rating scale. * Is pregnant or breastfeeding, at Baseline, or planning t…