What are the IBMFS disorders?
Shwachman-Diamond Syndrome (SDS)
SDS patients have poor food absorption (malabsorption) and low white
blood cell counts (neutropenia). Most patients are diagnosed
in infancy. Males and females are affected equally.
- What are the major findings on physical examination?
- Short stature
- Problems with bones ("metaphyseal dysostosis", a
specific finding seen on x-rays).
- What is the age at diagnosis?
- The diagnosis of SDS is usually made in the first year of life.
- What is the pattern of bone marrow failure?
- Neutropenia (low white blood count; white
cells help the body fight off infection)
Anemia (low red
blood cell count) may develop (often with large red cells).
- Low platelet
count may develop (platelets are the cells in the blood which
help the blood to clot).
anemia is diagnosed when all 3 types of cells (red cells,
white cells and platelets) are abnormally low because the bone
marrow is not producing them.
- What specific kinds of cancer develop?
Leukemia (cancer of
the blood and bone marrow)
- How is SDS specifically diagnosed?
- Reduced digestive enzyme
production by the pancreas ("Pancreatic insufficiency"),
which can be measured by various laboratory or x-ray tests:
- Low serum trypsinogen and isoamylase (key digestive enzymes
made by the pancreas)
- Abnormal amounts of fat in the stool
- Low pancreatic enzymes after stimulation of the pancreas
- Small or fatty pancreas on ultrasound or CT scan imaging
of the pancreas
- Bone marrow failure
- Low neutrophils
in blood on at least 3 occasions
- May have low hemoglobin and/or
- Genetic testing
- The disease appears to be inherited in an autosomal recessive
manner. This means that illness occurs only if a person has
two abnormal (mutant) copies of the SDS gene.
Laboratories can now identify the specific genetic "error"
in many patients, in a gene called SBDS, which stands for
Shwachman Bodian Diamond Syndrome.