Shwachman-Diamond syndrome
Meaning of Shwachman-Diamond syndrome: An inherited fault in assembling ribosomes that starves the pancreas and the marrow of machinery they need more than most tissues.
Definition of Shwachman-Diamond syndrome
Shwachman-Diamond syndrome is a rare inherited disorder in which the pancreas fails to release digestive enzymes and the bone marrow produces too few white cells, neutrophils above all. Short stature and changes at the growing ends of bones are usual, and the risk of marrow failure and of leukemia is raised. A child develops it after inheriting a faulty copy of the gene from each parent.
Why does one gene affect such different organs?
The gene involved in most cases carries instructions for a protein needed to finish assembling ribosomes, the structures every cell uses to build proteins. When that assembly is impaired, the cells falling behind first are the ones manufacturing protein fastest. The pancreas produces enormous quantities of digestive enzyme, and the marrow turns out blood cells in the billions each day, so both struggle while other tissues manage. Conditions of this kind are grouped as ribosome disorders, and they share the same puzzle: a fault present in every cell of the body that shows itself in only a few organs.
What are the main features?
| Feature | How it shows |
|---|---|
| Pancreatic insufficiency | Greasy, foul-smelling stools and poor weight gain from infancy |
| Low neutrophil count | Repeated ear, chest and skin infections |
| Short stature | Height below what the rest of the family would predict |
| Skeletal changes | Abnormal formation at the growing ends of the long bones |
| Marrow failure | Counts falling across all three cell lines over time |
| Raised leukemia risk | Myelodysplastic syndrome and acute myeloid leukemia |
The two main problems move in opposite directions over the years. Digestion frequently improves during childhood as the pancreas recovers some function, so enzyme replacement needed early may be needed less later. The blood generally demands closer attention as time passes, with the marrow watched for a drift toward aplastic anemia or leukemia.
How is it recognized and followed?
Failure to thrive combined with fatty stools and a low neutrophil count in an infant is what usually prompts testing, since neither finding alone is unusual. Pancreatic enzyme levels in blood, imaging showing fat in place of pancreatic tissue, and genetic testing settle it. Neutrophil counts fluctuate rather than sitting steadily low, so one normal result does not close the question. Repeated bone marrow examination is the standard way of watching for change toward leukemia, and bone marrow transplantation addresses the blood problems while doing nothing for the pancreas.
Also known as
Used in a sentence
Shwachman-Diamond syndrome was confirmed by genetic testing after the pancreatic findings.
Good to know
The neutrophil count in this syndrome varies rather than staying steadily low, so a single normal result does not exclude it, and pancreatic function often improves with age while the blood problems do not.