What Is Shwachman-Diamond Syndrome?
Shwachman-Diamond syndrome (SDS) is a rare, inherited type of bone marrow failure. It usually affects the pancreas and bone marrow, but it also may have an impact on the skeletal system. Sometimes other parts of the body including the liver and teeth may be involved. About one in 77,000 people has Shwachman-Diamond syndrome.
The name of the condition comes from the doctors who were among the first to describe it, in 1964: Harry Shwachman, MD, and Louis Diamond, MD.
Shwachman-Diamond Syndrome Causes
Changes (mutations) in a person’s genes cause Shwachman-Diamond syndrome. In most cases, when parents are carriers of the changed gene, they don’t show signs of the disease.
SDS 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.
When a child inherits an autosomal recessive change, it means the parents are both carriers of the genetic change. When both parents are carriers, there is a 25% chance that their child will have the condition.
Shwachman-Diamond syndrome-like diseases can also be caused by an autosomal dominant genetic change. “Dominant” indicates 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.
When a child inherits an autosomal dominant change, it means that only one of the parents has the genetic change. When only one parent has the genetic change, there is a 50% chance that their child will have 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.
Shwachman-Diamond Syndrome Symptoms
When a child is born with Shwachman-Diamond syndrome, symptoms may show up by 4 to 6 months of age. However, some people do not show their symptoms at a young age. Rarely, teens and adults are diagnosed with SDS.
A person may have some or all of the common symptoms linked to SDS. Symptoms can vary in severity.
Common symptoms include:
- Problems eating and digesting food
- Missing digestive enzymes
- Loose bowel movements or diarrhea
- Failure to thrive (not gaining weight or growing) or slow growth
- Anemia (not enough healthy red blood cells to carry oxygen)
- Neutropenia (low white blood cell count)
- Thrombocytopenia (low platelet count)
- Bruising or bleeding problems
- Skeletal problems, such as scoliosis (spine curvature)
- Delayed tooth development
- Intellectual disability
- Low muscle tone
- Liver problems
- Frequent infections
- Low energy or fatigue
Shwachman-Diamond Syndrome Diagnosis
The diagnosis of Shwachman-Diamond syndrome starts with a physical exam and symptom check. Blood tests can determine problems with the white blood cells, red blood cells or platelets. A physician may also order tests to check pancreas, kidneys and liver function.
Genetic testing can show changes in a child’s SBDS, DNAJC21, EFL1 and SRP54 genes. Parents can undergo testing, too, to see if they are carriers of these genetic changes.
Shwachman-Diamond Syndrome Treatment
Although there is not a cure for Shwachman-Diamond syndrome at this time, treatment can help manage a child’s symptoms.
Common treatments include:
- Pancreatic enzyme supplements
- Vitamin supplements
- Diet changes
- Blood transfusions
- Antibiotics for infections
- Granulocyte-colony stimulating factor (G-CSF) to treat low white blood cell count
- Hematopoietic stem cell transplantation (infusion of stem cells)
- Orthopaedic surgery or nonsurgical interventions
- Dental care
Shwachman-Diamond Syndrome Long-Term Outlook
Because Shwachman-Diamond syndrome is a bone marrow disorder, children who have the condition are at increased risk of blood disorders and cancers. For example, they are more likely to develop myelodysplastic syndrome (MDS), acute myeloid leukemia (AML) and other conditions.
Children with Shwachman-Diamond syndrome may also require frequent doctor visits and regular blood and bone marrow testing to monitor their health and receive treatments. But with expert care, most can lead normal lives.