Chronic Neurovisceral ASMD (NPA/B)
Chronic Neurovisceral ASMD (NPA/B) is characterized by slower progression of neurological degeneration and prolonged survival that distinguishes it from the infantile form. Neurologic involvement is highly variable in these patients and can present as early as 3 years of age. Typically, the age when the onset of neurologic involvement presents itself, correlates with disease severity and rate of progression.
Neurological symptoms can include ataxia, hypotonia/hyporeflexia due to loss of motor function and cognitive decline, while the multi-system disease manifestations are the similar to those with more severe chronic visceral ASMD, and premature death during childhood or early adulthood.
Currently there are no approved therapies for Chronic Neurovisceral ASMD (NPA/B), and disease management revolves around addressing the individual symptoms a patient might be experiencing. An enzyme replacement therapy (ERT) is under development for chronic visceral ASMD (NPB), but has no effect on the neurologic manifestations of this disease. Patients with limited neurological involvement could potentially benefit from and may be candidates for ERT.