What Causes Shwachman-Diamond Syndrome?
Changes (mutations) in a person’s genes cause Shwachman-Diamond syndrome (SDS). In most cases, when parents are carriers of the changed gene, they don’t show signs of the disease.
Shwachman-Diamond syndrome is usually caused by an autosomal recessive genetic change.
- “Autosomal” refers to a change that happens in the non-sex chromosomes.
- “Recessive” means that a child inherits two copies of the changed gene (one from each parent).
The autosomal recessive gene associated with almost all of those with Shwachman-Diamond syndrome is SBDS. Some diseases with symptoms similar to Shwachman-Diamond syndrome are caused by changes in the autosomal recessive genes DNAJC21 and EFL1.
If a child has an autosomal recessive change, it means both parents carry the same genetic change, even though they don’t have the condition themselves. When two carriers have a baby, there’s a 25% chance that the child will have the condition.
Shwachman-Diamond syndrome-like diseases can also be caused by an autosomal dominant genetic change. “Dominant” means that a child only needs one copy of the changed gene to have the condition. The copy can come from either parent. The autosomal dominant gene is SRP54.
If a child has an autosomal dominant change, it means only one parent carries that genetic change. When just one parent has it, there’s a 50% chance their child will inherit the condition.
In some cases, a child can have a new mutation in the SRP54 gene. This means neither of their parents has the genetic change, and it is not inherited.
About 10% of children diagnosed with Shwachman-Diamond syndrome do not have a known genetic change. It is not clear why they develop the condition.
