RARE METABOLIC DISEASE
Our commitment is to patients and families living with rare metabolic diseases – because rare doesn’t mean alone.
Rare metabolic diseases typically result from a missing or defective enzyme which is needed to convert one chemical into another. The type of metabolic disease depends on which enzyme is affected. For example, in Arginase 1 Deficiency, patients have a mutation in the gene that codes for arginase 1, the enzyme responsible for the breakdown of arginine. Without a properly functioning arginase 1, arginine accumulates in the body and can reach toxic levels.
Metabolism describes the network of life sustaining chemical reactions in the body, including breaking down food, recycling cellular waste, generating energy and powering the body’s growth. Because of this range of functions, manifestations of metabolic disorders vary widely but may include poor growth, developmental delay, intellectual disability, movement disorders, muscle weakness and seizures.
While there are many types of rare metabolic disorders, we focus on helping patients with devastating, progressive metabolic diseases with ineffective treatment options. Our current areas of focus are:
- Homocystinuria
- Arginase 1 Deficiency
With a deep understanding of the relationship between metabolites and disease, we are working to bring better treatment options to patients with rare metabolic disorders.

Cystathionine beta synthase (CBS) deficiency, also known as Classical Homocystinuria, is a serious and progressive metabolic disorder characterized by elevated levels of the amino acid homocysteine. This toxic buildup of homocysteine leads to a wide range of life-altering complications, including thromboembolic vascular events, skeletal abnormalities (including severe osteoporosis), developmental delay, intellectual disability, lens dislocation and severe near sightedness. The condition also results in early death.
Homocystinuria is frequently treated with vitamin B6 (pyridoxine) but its estimated that half of Homocystinuria patients are not responsive to this treatment. Patients who are unable to control their homocysteine levels with available treatments are forced to rely on dietary restriction, which is challenging to comply with and often has limited effect. Homocystinuria is a rare condition with an estimated 3,000-3,300 patients in the U.S.
Arginase 1 Deficiency (ARG1-D)
ARG1-D is an inherited metabolic disease that is often diagnosed in early childhood and worsens over time. ARG1-D is caused by the body’s inability to break down arginine, resulting in persistently high levels. Although, arginine is an important amino acid for the body’s normal function, too much arginine can have a devasting impact on the patient’s health and quality of life. Patients with ARG1-D experience muscle tightness (spasticity), missed developmental milestones, intellectual disability, seizures and early death.
ARG1-D is considered an ultra-rare disorder with an estimated 250 patients in the U.S. Although ARG1-D can be diagnosed through newborn screening, simple blood tests or genetic testing, it is often missed – resulting in patients having a delayed or incorrect diagnosis.
Harnessing Human Enzyme Therapeutics
