Dislocated Lenses

The Links to Marfan Syndrome and Diet
 
 
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Contents:

• Overview
• Causes of Dislocated Lenses
• Molybdenum, Sulfur and Copper
• Summary

Overview

Dislocated lenses are one of the hallmark features of Marfan syndrome. They are also well established conditions that occur in a variety of nutritional deficiencies or imbalances, and in the genetic/nutritional disorder known as homocystinuria. Is Marfan syndrome really a genetic disorder unrelated to nutrition, as many doctors believe, or could it be environmentally linked to the other known causes of dislocated lenses? Could a common thread be imbalances in the interdependent nutrients of copper, molybdenum and sulfur? This site explores nutrition as a factor in dislocated lenses occurring in Marfan syndrome.

Causes of Dislocated Lenses

Besides Marfan syndrome, established causes of dislocated lenses include:

1. Molybdenum cofactor deficiencies - These may result in abnormalities of sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase. All of these are molybdenum activated enzymes.  Molybdenum cofactor deficiencies are described as inborn errors of metabolism, though sulfite oxidase deficiencies are also known to be caused by environmental factors. For example, sulfite oxidase can be caused in rats through exposure to tungsten. People with sulfite oxidase deficiencies are sensitive to exposure to environmental sulfur. Sulfite oxidase deficiency is often treatable through a diet low in sulfur amino acids.

A study on Medline shows that a patient with both a molybdenum cofactor deficiency and sulfite oxidase deficiency was found to have a Marfan-like habitus with dislocated lenses, vertebral abnormality (i.e., scoliosis), learning disabilities, and hematuria. Are people diagnosed with Marfan syndrome and related disorders ever screened for molybdenum cofactor deficiencies or isolated sulfite oxidase deficiencies? If not, it seems like they should be, since clinically it seems like they can have similar symptoms. I wonder how many geneticists would know to check for these conditions.

2. Homocystinuria - A hereditary metabolic disorder involving methionine, a sulfur-containing essential amino acid. In homocystinuria, abnormally high concentrations of homocysteine and its precursor, methionine, are found in the blood plasma. In addition to dislocated lenses, patients with homocystinuria also have Marfan-like habituses and learning disabilities, features commonly found in Marfan syndrome. 

It is well established that many cases of homocystinuria respond to dietary treatment. If dietary supplements can help homocystinuria, could there be a dietary treatment for Marfan syndrome?

Copper, Molybdenum and Sulfur

Geneticists believe that Marfan syndrome is caused solely by a genetic fibrillin mutation unrelated to nutrition. But is it? What researchers believe to be true is not necessarily what is supported by actual medical studies. Molybdenum cofactor deficiencies, sulfite oxidase deficiency and homocystinuria are all linked to problems with sulfur amino acid metabolism, and all may produce overlapping features with Marfan syndrome such as dislocated lenses and the Marfan habitus (tall stature, pectus excavatum, scoliosis and low body weight).  The table below shows the links between molybdenum cofactor deficiency, homocystinuria and Marfan syndrome. Could Marfan syndrome be biochemically linked with the other two disorders? Could it also be linked to sulfur? Could it be influenced by diet? It would make an interesting study to find out.

Common Factors in Disorders Associated with
Dislocated Lenses

Molybdenum, sulfur and copper share a complex interrelationship. They each are cofactors for the other two. This is known as the copper-molybdenum-sulfur triangle. Imbalances of one of these nutrients can cause imbalances in the other two. The nutritional aspects of this triangle has been studied extensively in animals, but unfortunately less so in humans. Perhaps the relationship may also play a role in people with dislocated lenses, including those diagnosed with Marfan syndrome. 

Interestingly, patients with homocystinuria have been found to have abnormal levels of copper. That means the disorder has biochemical links to both copper and sulfur, two out of the three elements in the copper-molybdenum-sulfur triangle. Do patients with homocystinuria have abnormalities of molybdenum, too? It would be interesting to find out.

Patients with dislocated lenses caused by molybdenum cofactor deficiencies and isolated sulfite oxidase deficiencies usually have low uric acid levels. Interestingly, molybdenum is known to raise uric acid levels, which is why people with gout, a condition of too high uric acid levels, are told to avoid molybdenum supplements.

Foods high in purines such as broth, asparagus, gravy, mushrooms and organ meats also raise uric acid levels and are also bad for gout. It would be interesting to find out what effect molybdenum rich foods and/or a diet high in purines aimed at raising uric acid levels would have on people with dislocated lenses caused by molybdenum cofactor deficiencies and isolated sulfite oxidase deficiencies. It would also be interesting to find out if Marfans have low uric acid levels, too, and if they do, what effect a diet aimed at raising uric acid levels would have on their conditions, especially on Marfan patients with dislocated lenses.

Summary

Dislocated lenses have a variety of known causes besides Marfan syndrome. Three of the other known causes of dislocated lenses, molybdenum cofactor deficiencies, isolated sulfite oxidase deficiencies and homocystinuria, are all associated with abnormalities of sulfur amino acid metabolism. Besides dislocated lenses, all three of these disorders plus Marfan syndrome all share the feature of the Marfan habitus - tall, slender with long limbs and skeletal defects such as pectus deformities and scoliosis.

Could Marfan syndrome be related to a problem with sulfur metabolism, too? Could it be treated by dietary modifications? People have told me it is not possible for Marfan syndrome to be treatable through diet because is a genetic disorder. I disagree that that is a valid conclusion because many genetic disorders, including homocystinuria, have been found to be treatable through dietary modifications. Additionally, the case for Marfan syndrome being caused by mutations in fibrillin genes alone is illogical, considering that a large number of studies conducted over the past several years have consistently shown that most Marfans do not even have fibrillin mutations, and that many people who have fibrillin mutations don't have Marfan syndrome. (See my section on fibrillin for more on this subject.)

Perhaps, like sulfite oxidase deficiencies and homocystinuria, Marfan syndrome can be impacted by both diet and genes. It seems unlikely to me that the similarities between the three disorders and molybdenum cofactor deficiencies are all due to random coincidence. It is reasonable to conclude that they all may be biochemically related. Sulfur metabolism abnormalities are the common link between homocystinuria, molybdenum cofactor deficiency and isolated sulfite oxidase deficiency. Perhaps it is also a common link between those three disorders and Marfan syndrome, too.

Beyond those features that that are covered in this section, many of the other features of Marfan syndrome also have nutritional links. These include calcification of the heart valves and mitral valve prolapse. (See my main section on Marfan syndrome for more information on this.) 

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