JLK-247

JLK-247 is an experimental gene replacement therapy developed by Phoenix Nest for the treatment of Sanfilippo syndrome Type C (Mucopolysaccharidosis IIIC or MPS IIIC). The therapy utilizes a self-complementary adeno-associated virus serotype 9 (AAV9) vector to deliver a functional copy of the *HGSNAT* gene directly to the central nervous system via intrathecal administration. The biological target is the enzyme heparan sulfate acetyl-CoA:α-glucosaminide N-acetyltransferase (HGSNAT), which is deficient in patients with MPS IIIC. By restoring HGSNAT enzyme activity, JLK-247 aims to prevent the toxic accumulation of heparan sulfate in tissues, thereby halting or slowing the progression of severe neurological damage. The program has received FDA Orphan Drug designation and is currently in preclinical development with toxicology studies supported by NIH/NINDS grants.