THE SOCIETY FOR INHERITED METABOLIC DISORDERS

Joint Statement
April 11, 2013

CARNITINE AND INBORN ERRORS OF METABOLISM:

We appreciate the concern of patients and families following recent report in Nature Medicine^* that higher carnitine intake in diet can lead to production in the intestine of metabolites that may lead to increased risk of atherosclerosis later in life. These new data remind us of the need to consider and carefully study the risks and benefits of all treatments for metabolic disorders. Nevertheless, and respecting the possible importance of this finding for public health, the professional societies undersigned also point out that individuals with some inborn or acquired errors of metabolism are prescribed carnitine therapy by their health care providers in an effort to protect from various severe consequences of their underlying medical condition. Individuals who have been prescribed carnitine for treatment of an inborn or acquired error of metabolism should consult with their health care provider before making any changes in therapies or any other medical management.

Society for Inherited Metabolic Disorders
Society for the Study of Inborn Errors of Metabolism
Mitochondrial Medicine Society
Genetic Metabolic Dietitians International
The Garrod Association

^*Nature Medicine 2013, April. Intestinal microbiota metabolism of L-carnitine a nutrient in red meat, promotes atherosclerosis. http://www.nature.com/nm/journal/vaop/ncurrent/abs/nm.3145.html

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POINTS TO CONSIDER AND DISCUSS
The authors of the paper that has generated the intense media attention and public discussion have carefully pointed out that further investigation is needed to understand the implications of their findings; their research focused on the general population and not on individuals with metabolic disorders. Nevertheless, the media attention to this issue, and the conclusions drawn by some media outlets from the reported scientific findings, has generated considerable anxiety in the community of those with metabolic disorders. This conversation provides opportunity to emphasize several important points:

• All therapies have risks and benefits – even those therapies based on natural substances, and even when those substances are synthesized by the human body, such as carnitine
• Inborn errors of metabolism are individually rare and therefore there is often relatively little information known about natural history and therapy; the undersigned societies all continue to call for additional research in these conditions, including therapies
• Inborn errors and acquired disorders of metabolism are collectively common, and therefore large numbers of people and families will be impacted by the need to understand the implications of population studies on individuals with rare disorders; this further underscores the need for additional research in rare conditions
• Objective study of all therapies to determine risks and benefits must be done in appropriate populations
• Families and health care providers need to recognize that in some cases public health prevention recommendations will conflict with what is understood to be medically necessary individual therapies; in such cases more research will be needed to better understand any conflict
• Patients and families should be told about risks associated with therapies. They should also be told how relevant those risks are to their particular situation. For each individual, health care providers and patients and families must balance risks and benefits of each therapy on an individual basis.
• In the case of carnitine, for some patients the balance between immediate risk of death without carnitine and the possibility of an increased risk of atherosclerosis in future life leads to a simple decision to continue therapy. For other conditions, the value of carnitine in therapy may be less well understood and the discussion between patient/family and health care provider about risks and benefits of therapy will be more complex.
• In all cases, the undersigned societies recommend that individuals who are prescribed carnitine should consult with their health care providers before making any changes in their therapy.