In the United States, according to the National Institutes of Health, between two and four of every 100,000 children are born with Batten disease. They can get it if both their parents are genetic carriers. There are 14 subtypes of the disease, each affecting a different gene, involving a different deficiency, and decreeing a different life span. Conner was diagnosed with subtype CLN2, distinguished by the absence of TPP1. Symptoms initially appear around the age of two; a speech delay is often the first noticeable sign of disease. After that come seizures, language regression, motor dysfunction, and blindness. Patients die between the ages of eight and twelve.
Amitha Kalaichandran — The Atavist Magazine