WHAT IS CYSTINOSIS?
Cystinosis is a rare, genetic condition that affects about 500 to 600 people in the United States and an estimated 2,000 worldwide. Symptoms usually appear within a child’s first year of life.
- In people with cystinosis, cystine (an amino acid) builds up in the body’s cells and the cells are unable to remove it
- When cystine builds up, it forms crystals within cells that can lead to long-term damage to the body’s organs—including the kidneys, eyes, liver, muscles, pancreas, and brain
- This damage cannot be reversed, but it can be delayed or prevented
What is nephropathic cystinosis?
Nephropathic cystinosis is the most severe and most common form of cystinosis, making up 95% of all cases. Nephropathic cystinosis causes severe damage to kidneys and other organs all over the body.
Nephropathic cystinosis generally affects boys more than girls and most often occurs in blond-haired, blue-eyed children of European descent. However, people of all races and ethnic backgrounds can be affected. Its symptoms usually appear within a child’s first year of life.
How cystinosis affects the body
Cystinosis can affect nearly every organ of the body. Treatment can prevent or slow some effects, but existing damage cannot be reversed.
Sensitivity to light (photophobia) childhood and adulthood Blindness
childhood and adulthood
Poorly working thyroid (hypothyroidism) childhood and adulthood
Diabetes childhood and adulthood
Fanconi syndrome infancy, childhood, and adulthood Kidney failure childhood and adulthood
Muscle weakness and decreased muscle mass (myopathy) childhood and adulthood
Visual or learning issues childhood and adulthood
Trouble swallowing childhood and adulthood
Problems breathing adulthood
Male reproductive organs*
Not being able to father children naturally (infertility) adulthood
Softening or weakening of bones (rickets)
infancy, childhood, and adulthood
Cystinosis has not been shown to cause infertility in women. If you are pregnant, planning on becoming pregnant, or breastfeeding, talk with your doctor about which treatments may be right for you.
What is Fanconi syndrome?
Over time, nephropathic cystinosis causes damage to the kidneys. This damage makes the kidneys increasingly unable to absorb essential nutrients and filter out the body’s waste—a disorder known as Fanconi syndrome. In people with Fanconi syndrome, nutrients that would normally be absorbed are passed through the kidneys and are eliminated in pee (urine).
Fanconi syndrome is often the first sign of cystinosis, as cystinosis often presents through Fanconi syndrome and leads to cystinosis diagnosis. Cystinosis can be discovered through a white blood cell cystine level test.
Eventually, the damage caused by cystinosis causes the kidneys to fail completely, which can be treated only with dialysis (an artificial means of getting rid of the body’s waste) and, ultimately, a kidney transplant. A kidney transplant cures failure in the affected kidney, but not cystinosis. Post-transplant, patients must continue cystine-depleting therapy (CDT) to help delay or reduce new damage to other organs.
How is cystinosis passed down?
Cystinosis is an inherited disease that is passed from parent to child, when a gene that doesn’t work right leads to problems with the way cystine is stored in the body. Cystinosis can only develop in children who receive a non-working copy of the cystinosis gene from each parent.
How cystine levels are managed
The damage from cystinosis cannot be undone, but it can be delayed or prevented with treatment. The impact of sticking to treatment is noticeable, even if you may not notice it yourself. Testing shows how CDTs are working inside your body, and what is happening with your cystine levels. CDTs lower cystine levels, which is why it’s important that you take a CDT on time and as prescribed, even if you look and feel fine. Work with your healthcare team to plan a schedule for cystine level testing. Find out more details about cystine level testing.
One medical study showed that people who took their doses of cysteamine therapy on time had lower average cystine levels compared with people who missed a dose or took their medicine late, who had a 29% increase in cystine levels.
It’s a lifelong condition, but treatments such as CDT and kidney transplant have allowed people with cystinosis to live longer.