The purpose of this study is to determine whether BMN 190 is safe and effective in the treatment of patients with Late-Infantile Neuronal Ceroid Lipofuscinosis Type 2 (CLN2) disease.

The purpose of this study is to determine whether BMN 190 is safe and effective in the treatment of patients with Late-Infantile Neuronal Ceroid Lipofuscinosis Type 2 (CLN2) disease. This is an open label Phase 1/2 study conducted in patients with CLN2 disease. Efficacy measures (disease rating scale and MRI) will be compared to a natural history control.

The study will be conducted under cGCP and patients will be closely monitored.

Inclusion Criteria:

• Has a diagnosis of CLN2 determined by TPP1 enzyme activity (dried blood spot) available at study entry. If no genotype information is available, blood will be collected for CLN2 gene analysis at baseline. In addition, blood for TPP1 enzyme activity (dried blood spot) will be collected at baseline to be analyzed centrally
• Has mild to moderate disease documented by a two-domain score of 3- 6 on motor and language domains of the Hamburg Scale, with a score of at least 1 in each of these two domains
• Written informed consent from parent or legal guardian and assent from subject, if appropriate
• Has the ability to comply with protocol requirements, in the opinion of the investigator
• Seizures are stable in the judgement of the investigator

Exclusion Criteria:

• Is less than 3 years old at enrollment
• Is 16 years old or older at enrollement
• Has another inherited neurologic disease, e.g. other forms of CLN or seizures unrelated to CLN2 (patients with febrile seizures may be eligible)
• Has another neurological illness that may have caused cognitive decline (e.g., trauma, meningitis, hemorrhage) before study entry
• Requires ventilation support, except for noninvasive support at night
• Has received stem cell, gene therapy, or ERT for CLN2
• Has contraindications for neurosurgery (e.g., congenital heart disease, severe respiratory impairment, or clotting abnormalities)
• Has contraindications for MRI scans (e.g., cardiac pacemaker, metal fragment or chip in the eye, aneurysm clip in the brain)
• Has generalized motor status epilepticus within 4 weeks before the First Dose visit, taking care that status epilepticus is on clinical examination and not only electroencephalogram (EEG) (enrollment may be postponed)
• Has severe infection (e.g., pneumonia, pyelonephritis, or meningitis) within 4 weeks before the First Dose visit (enrollment may be postponed)
• Is prone to complications from intraventricular drug administration, including patients with hydrocephalus or ventricular shunts
• Has known hypersensitivity to any of the components of BMN 190
• Has received any investigational medication within 30 days before the first infusion of study drug or is scheduled to receive any investigational drug other than BMN 190 during the course of the study
• Has a medical condition or extenuating circumstance that, in the opinion of the investigator, might compromise the subject's ability to comply with the protocol required testing or procedures or compromise the subject's well being, safety, or clinical interpretability
• Pregnancy any time during the study