What is homocystinuria?
Homocysteine is an amino acid that is produced by the body by chemically altering adenosine. Amino acids are naturally made products, which are the building blocks of all the proteins in the body.
What are the symptoms for homocystinuria?
The symptoms will depend on the type of homocystinuria. Symptoms generally develop during the first years of life. However, some people experience symptoms during adulthood. Symptoms are often vague and difficult to detect. The most common forms of this disorder may involve the following symptoms:
- dislocation of the lenses in the eyes
- abnormal blood clots
- osteoporosis, or weakening of the bones
- learning disabilities
- developmental problems
- chest deformities, such as a protrusion or a caved-in appearance of the breastbone
- long, spindly arms and legs
Less common variations involve these additional signs and symptoms:
- megaloblastic Anemia, an Anemia involving larger-than-normal red blood cells
- failure to thrive
- intellectual disabilities
- movement and gait abnormalities
What are the causes for homocystinuria?
Certain genetic mutations present at birth cause this disease. More than 150 mutations that cause homocystinuria have been found in the gene cystathionine beta-synthase, which is also known as the CBS gene. The CBS gene holds instructions for making an enzyme that uses vitamin B-6 to metabolize the amino acids homocysteine and serine. The mutations prevent the normal functioning of the CBS gene. This results in a buildup of homocysteine and other toxins that damage the nervous system, which includes the brain, and the vascular system.
In rare cases, mutations in other genes like MTHFR, MTR, or MTRR cause the disorder. Homocystinuria is an autosomal recessive trait. This means that for a child to have the signs or symptoms of this condition, they would need to inherit the mutated gene from both parents.
What are the treatments for homocystinuria?
There’s no cure for homocystinuria. High doses of vitamin B-6 are a successful treatment for about half of the people with this disorder. If you respond well to this supplementation, it’s likely that you’ll have to use daily vitamin B-6 supplements for the rest of your life.
Alternatively, if you don’t experience positive results from this therapy, your doctor may recommend eating a diet low in foods containing the amino acid methionine. People diagnosed at an early stage have had positive responses after switching to this diet.
Your doctor may also recommend taking betaine (Cystadane). Betaine is a nutrient that works to remove homocysteine from the blood. Taking a folic acid supplement and adding the amino acid cysteine to the diet are helpful.
What are the risk factors for homocystinuria?
Since homocystinuria is passed from parents to children, a family history of the disorder places children at an increased risk of developing this condition. The disorder is more common in:
Is there a cure/medications for homocystinuria?
Homocystinuria is a condition caused due to the deficiency of cystathionine beta-synthase or methionine synthase. This enzyme is important in the processing of an amino acid called methionine. Most of the time, it is caused due to an autosomal recessive condition. However, sometimes it is caused due to the deficiency of vitamins B12, folate, and B6.
- Since it is a genetic disorder, there is nos specific treatment for this particular disease.
- It is usually prevented by a diet rich in vitamins B6, B12, and folate.
- They will need vitamin B6 supplements for the rest of their lives.
- Sulfur content in the food should also be maintained at a relevant level to reduce the synthesis of methionine in the body.
- Betaine can also be used to reduce the presence of homocysteine by converting it into methionine.
- The methionine created in this form is removed via body protein.
- This treatment is usually combined with a low protein disease, as the amount of conversion can be low.
- Generally, patients with this disease are recommended to have low protein and high-fat food to reduce the amount of methionine in the body.
- The life expectancy of the patient suffering from homocystinuria is reduced when the patient doesn't undergo proper treatment at its early stage.
Eye defects,Urinary tract issues
Vitamin B6 therapy,Low methionine diet
Dislocation of the lenses in the eyes,Nearsightedness,Abnormal blood clots,Osteoporosis, or weakening of the bones,Learning disabilities,Developmental problems,Chest deformities, such as a protrusion or a caved-in appearance of the breastbone,Long, spindly arms and legs