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  1. 1. University of Kalamoon Nutrition department Dr. Louay Labban
  2. 2. <ul><li>Amino acid disorders (AAs) are a group of rare inherited conditions. They are caused by enzymes that do not work properly. </li></ul>
  3. 3. <ul><li>Protein is made up of smaller building blocks called amino acids. A number of different enzymes are needed to process these amino acids for use by the body. </li></ul>
  4. 5. <ul><li>Because of missing or non-working enzymes, people with amino acid disorders cannot process certain amino acids. </li></ul><ul><li>These amino acids, along with other toxic substances, then build up in the body and cause problems. </li></ul>
  5. 6. <ul><li>The symptoms and treatment vary between different amino acid disorders. They can also vary from person to person with the same amino acid disorder. </li></ul>
  6. 7. <ul><li>Amino acid disorders are inherited in an autosomal recessive manner and affect both males and females </li></ul>
  7. 8. <ul><li>Tyrosinemia I </li></ul><ul><li>Tyrosinemia II </li></ul><ul><li>They are different in the missing enzyme, some symptoms and the final products that causes toxicity. </li></ul>
  8. 9. <ul><li>Tyrosinemia 1 is sometimes also called: </li></ul><ul><li>Hereditary Infantile tyrosinemia </li></ul><ul><li>Hepatorenal tyrosinemia </li></ul><ul><li>Fumarylacetoacetase deficiency </li></ul><ul><li>Fumarylacetoacetate hydrolase deficiency </li></ul>
  9. 10. <ul><li>This condition is inherited in an autosomal recessive manner. It affects both boys and girls equally.  </li></ul><ul><li>Everyone has a pair of genes that make the FAH enzyme. </li></ul>
  10. 11. <ul><li>In children with tyrosinemia 1, neither of these genes works correctly. These children inherit one non-working gene for the condition from each parent. </li></ul>
  11. 12. <ul><li>Parents of children with tyrosinemia 1 rarely have the condition themselves. Instead, each parent has a single non-working gene for the condition. They are called carriers . </li></ul><ul><li>Carriers do not have the condition because the other gene of this pair is working correctly.    </li></ul>
  12. 13. <ul><li>Tyrosinemia is a condition or one type of amino acid disorder . People with tyrosinemia 1 have problems breaking down an amino acid called tyrosine from the food they eat. </li></ul>
  13. 14. <ul><li>If not treated, the condition causes severe liver disease and other serious health problems.    </li></ul>
  14. 15. <ul><li>In order for the body to use protein from the food we eat, it is broken down into smaller parts called amino acids. </li></ul><ul><li>Special enzymes then make changes to the amino acids so the body can use them.  </li></ul>
  15. 16. <ul><li>Tyrosinemia 1 occurs when an enzyme, called fumarylacetoacetase (FAH), is either missing or not working properly. When FAH is not working, it cannot break down tyrosine. Tyrosine and other harmful substances then build up in the blood. </li></ul>
  16. 17. <ul><li>One of these substances is called succinylacetone. When it builds up in the blood, it causes serious liver and kidney damage. It may also cause episodes of weakness or pain.      </li></ul>
  17. 19. <ul><li>Genes tell the body to make various enzymes. People with tyrosinemia 1 have a pair of genes that do not work correctly. </li></ul>
  18. 20. <ul><li>Because of the changes in this pair of genes, the FAH enzyme either does not work properly or is not made at all </li></ul>
  19. 21. <ul><li>When both parents are carriers, there is a 25% chance in each pregnancy for the child to have tyrosinemia 1. There is a 50% chance for the child to be a carrier, just like the parents. And, there is a 25% chance for the child to have two working genes.  </li></ul>
  20. 23. <ul><li>The symptoms can vary a great deal from person to person. There are two types of tyrosinemia 1. The more common form happens in infants. The less common form is seen in older children and adults.  </li></ul>
  21. 24. <ul><li>Babies usually show effects of the condition within the first few months of life. Some of the first symptoms may be: </li></ul>
  22. 25. <ul><li>diarrhea and bloody stools </li></ul><ul><li>vomiting </li></ul><ul><li>poor weight gain </li></ul><ul><li>extreme sleepiness </li></ul><ul><li>irritability </li></ul><ul><li>“ cabbage-like” odor to the skin or urine </li></ul>
  23. 27. <ul><li>Liver problems are common. They can lead to: </li></ul><ul><li>enlarged liver </li></ul><ul><li>yellowing of the skin </li></ul><ul><li>tendency to bleed and bruise easily </li></ul><ul><li>swelling of the legs and abdomen </li></ul>
  24. 28. <ul><li>Kidney problems also happen and can lead to: </li></ul><ul><li>rickets , a bone thinning condition </li></ul><ul><li>delays in walking </li></ul>
  25. 29. <ul><li>Without prompt and careful treatment, babies with severe liver and kidney problems usually die. </li></ul><ul><li>Some babies also have episodes that include: </li></ul><ul><li>pain or weakness, especially in the legs </li></ul>
  26. 30. <ul><li>breathing problems </li></ul><ul><li>rapid heartbeat </li></ul><ul><li>seizures </li></ul><ul><li>coma, sometimes leading to death  </li></ul>
  27. 31. <ul><li>Goals of dietary management for infants and children are to: </li></ul><ul><li>Support an appropriate rate of growth </li></ul><ul><li>Support normal intellectual development </li></ul><ul><li>Maintain optimal nutritional status </li></ul><ul><li>Provide adequate nourishment </li></ul>
  28. 32. <ul><li>5. Prevent neurological crisis </li></ul><ul><li>6. Prevent liver and renal function problems </li></ul><ul><li>7. Prevent formation of tyrosine crystals in the eyes (this occurs with elevated plasma tyrosine levels) </li></ul>
  29. 33. <ul><li>Treatment consists of medication and a diet low in tyrosine and another amino acid called phenylalanine (phe). </li></ul>
  30. 34. <ul><li>The low-tyrosine/phenylalanine diet is made up of a special medical formula and carefully chosen foods. You must start the treatment as soon as you know your child has the condition. </li></ul>
  31. 36. <ul><li>The following treatments are often recommended for children with tyrosinemia 1: </li></ul>
  32. 37. <ul><li>A medication called nitisinone (Orfadin® ), also known as NTBC, is used to prevent liver and kidney damage. </li></ul>
  33. 38. <ul><li>It also stops the neurologic crises. The medication may also lessen the risk for liver cancer. Your child should start taking Nitisinone as soon as possible. </li></ul>
  34. 39. <ul><li>Nitisinone will increase the level of tyrosine in your child’s blood. So, a low-tyrosine diet is a very important part of treatment.     </li></ul>
  35. 40. <ul><li>Vitamin D supplements are sometimes used to treat children who have rickets.   </li></ul>
  36. 41. <ul><li>The special medical formula gives babies and children the nutrients and protein they need while helping keep their tyrosine levels within a safe range. </li></ul>
  37. 42. <ul><li>The diet is made up of foods that are very low in tyrosine and phenylalanine. This means your child will need to limit foods such as cow’s milk and regular formula </li></ul>
  38. 43. <ul><li>He or she will need to avoid: </li></ul><ul><li>meat </li></ul><ul><li>eggs </li></ul><ul><li>cheese. </li></ul><ul><li>Regular flour </li></ul><ul><li>dried beans </li></ul><ul><li>Nuts </li></ul><ul><li>peanut butter contain these amino acids and must also be limited. </li></ul>
  39. 44. <ul><li>Many vegetables and fruits have only small amounts of phenylalanine and tyrosine and can be eaten regularly in carefully measured amounts. </li></ul><ul><li>  </li></ul>
  40. 45. <ul><li>There are other medical foods such as special flours, pastas, and rice that are made especially for people with tyrosinemia 1. </li></ul>
  41. 46. <ul><li>Your child will have regular blood and urine tests to check: </li></ul><ul><li>amino acid levels </li></ul><ul><li>the amount of succinylacetone </li></ul><ul><li>nitisinone level </li></ul><ul><li>liver and kidney function  </li></ul><ul><li>These tests help your doctor and dietician figure out whether any changes to the medication or diet are needed. </li></ul>
  42. 47. <ul><li>Some experts suggest that children with tyrosinemia 1 have a CT or MRI scan of their liver once a year to check for scarring or cancer.  </li></ul>
  43. 48. <ul><li>Before nitisinone was available, liver transplantation was one of the main treatments for tyrosinemia 1. Now, nitisinone can prevent or reverse many of the liver problems. </li></ul>
  44. 49. <ul><li>Liver transplantation is still an option to prevent liver cancer. It may also be considered for children who show signs of liver cancer or liver failure. </li></ul>
  45. 50. <ul><li>Genetic testing for tyrosinemia 1 can be done on a blood sample. Genetic testing, also called DNA testing, looks for changes in the pair of genes that causes this condition. </li></ul>
  46. 51. <ul><li>Meeting Nutrient Requirements </li></ul><ul><li>For infants and young children with tyrosinemia, nutrient requirements are met using a combination of metabolic formula, breastmilk or infant formula, and/or natural foods. </li></ul><ul><li>  </li></ul>
  47. 52. <ul><li>The initial diet for treatment of tyrosinemia is based on the : </li></ul><ul><li>Age </li></ul><ul><li>Weight </li></ul><ul><li>general health status of the infant. </li></ul>
  48. 53. <ul><li>It is essential to initiate treatment (i.e., eliminate tyrosine and phenylalanine and provide adequate energy and total protein) as soon as the diagnosis is established.   </li></ul>
  49. 54. <ul><li>Blood levels of phenylalanine and tyrosine must be carefully monitored. </li></ul>
  50. 55. <ul><li>As the infant matures, small amounts of solid foods are introduced. The formula mixture should continue to contribute 75-80% of the child’s total nutrient intake. </li></ul>
  51. 57. <ul><li>Throughout childhood the diet must be monitored carefully and adjusted regularly based on plasma phenylalanine and tyrosine levels, growth, weight gain, and recorded intakes of phenylalanine, tyrosine, protein, and energy from foods. </li></ul>
  52. 58. <ul><li>Tyrosinemia type II is an autosomal recessive condition caused by a defect in the hepatic tyrosine aminotransferase gene responsible for converting tyrosine to 4-hydroxyphenylpyruvate. </li></ul>
  53. 59. <ul><li>It is characterized clinically by: </li></ul><ul><li>eye and skin lesions with neurological squeal </li></ul><ul><li>developmental delay </li></ul><ul><li>behavioral problems and self injurious behaviors also occurring frequently. </li></ul>
  54. 60. <ul><li>photophobioa, lacrimation, burning eye pain, inflamed conjunctiva Blistering lesions on the palms and soles Microcephaly Developmental delay Behavioral problems consequences </li></ul>
  55. 64. <ul><li>Newborn screen Tandem mass spectrometry </li></ul>
  56. 65. <ul><li>Treatment A low protein or special diet restricting phenylalanine and tyrosine will alleviate failure to thrive in days, the eye condition in weeks and the skin condition in months. </li></ul>
  57. 66. <ul><li>Maintaining tyrosine levels below 800µmol/l appears to be protective against pathology including neurological squeal. </li></ul>