Introduction to Homocystinuria

Homocystinuria is an autosomal recessive trait, which means a child are only diagnosed with homocystinuria if he or she inherit the mutations from both parents.

This disorder prevents the body from processing a specific amino acid called methionine.

• Amino acids are the building blocks of protein and methionine is needed in various proteins.
• The main cause of this disorder is the genetic mutations that are present at birth.
• Cystathionine-ß-synthase (CBS gene) is responsible for the production of an enzyme which uses Vitamin B6 to metabolize amino acids such as serine and homocysteine.
• However, the mutations found in the CBS gene prevent it from functioning normally. This lead to a buildup of toxins that can damage the brain and vascular system.

Some symptoms of Homocystinuria includes:

1) Long limbs

2) Nearsightedness

3) Learning disabilities

4) Spidery fingers

5) Knock knees

Some other more serious symptoms includes:

1) Downwards dislocation of the lense (Ectopia lentis)

2) Mental retardation

3) Chest deformities

4) Skeletal deformities

http://www.healthline.com/health/homocystinuria#Overview1

Diet plan for homocystinuria patient

Non-responders to vitamin B6 are treated with a low-methionine diet. Methionine restriction is achieved by limiting the intake of natural proteins in the diet. If the diet begins at an early stage, it can help reduce the risk of complications and the impact of intellectual disability. It must be continued for the individual’s lifetime and the diet should only begin after consultation with a dietician.

To prevent malnutrition of other amino acids, a methionine-free amino acid formula is also taken. There is a range of general methionine-free powders formulated to meet the nutritional needs of individuals of various ages. It contains a balanced mix of essential and non-essential amino acids, vitamins, minerals and minimal carbohydrates. In addition, special low-protein food products are widely available as well.  


The table below shows the types of food with the amount of methionine present:
 http://www.hcusupport.com/diet.htm

Vegetables that are high  in methionine	Broccoli, Mushroom, Cauliflower, Avocado, Bean sprouts, potatoes, Spinach, Green Peas, Corn
Vegetables that are low in methionine	Carrot, Beetroot, Tomatoes, Green, Red and Yellow Pepper, Eggplant, Green, Lettuce, Cucumber, Celery
Fruits that are high in methionine	Mandarin Oranges
Fruits that are low  in methionine	Watermelon, Honeydew melon, Apples, Pears, Cranberries, Raspberries, Blueberries, Strawberries, Mango, Plums, Banana, Pineapple, Apricots
Snacks that are high in methionine	All nuts such as Peanuts, Pistachio, Macadamia
Snacks that are moderate in methionine	Potato chips, French Fries, Hash browns, Pretzels
Other foods that are high in methionine	Tofu, dried beans like kidney beans, black beans, Tempeh