People with this condition should also avoid certain foods such as fava beans as these contain a related substance that is likely to cause a reaction.
Your doctor will be able to advise you of which drugs may be problematic for you and if necessary, your medications can be changed so that you can undergo your surgical procedure.
Many people with G6PD deficiency do not have any complications from the condition.
If you are identified as having this condition, it is important to avoid certain drugs and foods that may cause a problem. You should carry a card that identifies you as having the condition and advise medical and dental professionals about this condition in advance of any treatment you may need, so that they can take appropriate precautions.
If you think you may have the condition, you should ask your doctor to test you.
The following drugs are known to cause a reaction in people with the condition. These drugs should not be taken by people who are known to have the defect:
Sulfa drugs (used for urinary tract infections and some other infections)
Para-Amino Salicylic Acid (PAS) (a medication for malaria)
Phenazopyridine (used for pain relief and also as a urinary analgesic)
Analgesics containing pethidine or meperidine, such as Demerol or Darvon.
Dyes containing methylene blue
Trimethoprim (a sulfonamide)
Nitrofurantoin (an antibiotic)
Chloroquine (a blood thinner and also an antimalarial drug)
Phenytoin (used for epilepsy)
Mecobalamin (a B12 preparation)
Alkaptonuria is a rare genetic disorder where the enzyme defect causes a build-up of a substance called homogentisic acid in the body.
This substance is broken down (hydrolysed) in the body by an enzyme called Alkapton O-Methyltransferase, which is produced by certain cells in the body. Normally, these cells are plentiful but in alkaptonuria, they are not present in sufficient quantities to break down homogentisic acid.
The build-up of this acid in the body can cause damage to the skin, bone, cartilage, and connective tissue. It is these complications that cause most of the complications seen in this condition.
Early diagnosis and treatment can slow down the progression of the condition.
Exposure to ultraviolet light (the sun) speeds up the complications of this condition. By avoiding excessive sun exposure, a person with this condition can hope to live a relatively normal life span.
The exact effect that this condition will have on an individual is not predictable.
The following symptoms are seen in this condition:
Skin pigmentation (skin becomes darker)
Yellow to brown deposits under the skin
Bone abnormalities (such as bone shape changes, short stature, and micrognathia) may be present at birth or develop later in life.
Hip dislocations or other skeletal problems may develop.
Nerve problems (peripheral neuropathy)
Optic nerve damage and eye problems may develop.
The following complications may develop:
Aortic aneurysm (ballooning of the aorta, the major blood vessel leaving the heart)
Arthritis (inflammation of the joints) may develop in the spine and large joints.
Kidney stones are common.
The life expectancy of an individual with this condition depends on the exact location and type of cell that is defective and the organ system involved.
People with this condition are thought to have an increased risk of developing cancer, particularly osteosarcoma (bone cancer). There is also an increased risk of developing multiple cancers, such as osteosarcoma and leukemia.
The risk of developing leukemia is increased by five-fold over that in the general population.
The average age of onset of osteosarcoma is around 20 years.
This condition is inherited in an autosomal recessive manner. This means both copies of the gene (one from each parent) must be defective for a person to be affected by this disorder.
The parents of a person with an autosomal recessive condition each carry one copy of the defective gene, but do not show signs of the disorder.
If both parents carry one copy of the defective gene there is a:
1 in 4 chance, with each pregnancy, that you will have a child with the disorder.
1 in 2 chance, with each pregnancy, that you will have a normal child.
1 in 4 chance, with each pregnancy, that you will have an unaffected child, even if that child receives the defective gene from both parents.
The gene(s) involved in this condition is unknown. It has been known for some time that the condition is inherited in an autosomal recessive manner, but it was not until recently that the gene(s) responsible were identified.
Homogentisic aciduria (HGA), an autosomal recessive disorder also affects the breakdown of a pigment called homogentisic acid. HGA is known to cause a very similar condition to TSD.
The gene(s) that cause HGA were found to be the same as those that cause TSD.
TSD is now known to be caused by defects in two genes:
PALB2, also known as DNA repair gene PALB2, the product of which functions in the repair of DNA damage (Defects in this gene are associated with cancers).
PALB1, also known as DNA replication gene PALB1, the product of which is involved in the duplication of DNA.
TSD can be diagnosed by a physical examination combined with urine and blood tests.
Treatment for TSD is symptomatic. This involves maintaining proper nutrition and ensuring the prevention of fractures by limiting activity.
Surgery can be considered for reconstruction of the skull, if needed.
Prognosis is poor. Most affected individuals do not survive past the perinatal period (28 weeks of pregnancy).
The few who do reach adulthood usually do not survive past their teenage years.
Currently, there is no treatment to slow or reverse the course of this condition.
Early death, however, does not appear to be caused by the anemia or bone marrow failure (both of which can be treated). Rather, the cause of death is usually a complication such as cancer (e.g.
leukemia) or infection.
“This information is based on English language publications. Translations of these publications are available on request.”