What is Cystinosis?
What is Cystinosis?
What is
Cystinosis?
What is cystinosis?
Cystinosis is a rare but serious multi-system genetic disorder that initially manifests in the kidneys. If cystinosis goes untreated, it can be fatal.
Cystinosis is now considered manageable with treatment thanks to the availability of effective medication.
How CTNS Defects Cause Cystinosis
Cystinosis is caused by a genetic defect in the CTNS gene, which tells the body how to build an essential transporter protein called cystinosin. This defect is usually a deletion of a specific portion of the gene—the 57-kb segment. However, other types of defects on the CTNS gene or varied levels of deletion exist. These variations are responsible for how the disease can behave differently in different people.
Functioning CTNS Gene
Defective CTNS Gene
Defects in the CTNS gene prevent cystinosin from working properly or from being produced in the right amounts.
How CTNS Defects Cause Cystinosis
Cystinosis is caused by a genetic defect in the CTNS gene, which tells the body how to build an essential transporter protein called cystinosin. This defect is usually a deletion of a specific portion of the gene—the 57-kb segment. However, other types of defects on the CTNS gene or varied levels of deletion exist. These variations are responsible for how the disease can behave differently in different people.
Functioning CTNS Gene
Defective CTNS Gene
Defects in the CTNS gene prevent cystinosin from working properly or from being produced in the right amounts.
When cystinosin is not able to transport cystine, cystine begins to build up in cells, eventually forming crystals throughout the body:
Normal Lysosome
In a normal cell, cystinosin helps remove cystine from the cell’s lysosome, the part of the cell that digests and recycles materials
Mutated Lysosome
When cystinosin doesn’t work properly or isn’t present in the right amounts, cystine builds up in the lysosomes throughout the body—including in the eyes
Lysosomes are found inside of cells and contain enzymes which break down molecules into smaller pieces so that they can be recycled for other uses or carried away.
When cystinosin is not able to transport cystine, cystine begins to build up in cells, eventually forming crystals throughout the body:
Normal Lysosome
In a normal cell, cystinosin helps remove cystine from the cell’s lysosome, the part of the cell that digests and recycles materials
Mutated Lysosome
When cystinosin doesn’t work properly or isn’t present in the right amounts, cystine builds up in the lysosomes throughout the body—including in the eyes
Lysosomes are found inside of cells and contain enzymes which break down molecules into smaller pieces so that they can be recycled for other uses or carried away.
Recognized Types of Cystinosis
There are three types of cystinosis that have been recognized by doctors:
Nephropathic cystinosis
Other terms: Infantile cystinosis, classic cystinosis
- 95% of reported cases are this type; most severe
- Appears in infancy
- Affects the kidneys and other organ systems
Intermediate cystinosis
Other terms: Juvenile cystinosis, late-onset cystinosis
- Unknown how many cases are of this type
- Appears later in life
- Also affects the kidneys and other organ systems but may progress more slowly in the body than the most severe type of cystinosis