What is Shwachman Diamond Syndrome

Shwachman-Diamond Syndrome (SDS) is a rare, multisystem genetic disorder characterized primarily by pancreatic insufficiency, bone marrow dysfunction, and skeletal abnormalities. It is caused by mutations that impair ribosome assembly, leading to a wide range of clinical manifestations that typically appear in early childhood.

What body systems are affected by Shwachman-Diamond Syndrome?

Shwachman-Diamond Syndrome impacts several organ systems, most notably the pancreas and the bone marrow. The exocrine pancreas often fails to produce necessary digestive enzymes, leading to malabsorption. Additionally, Shwachman-Diamond Syndrome frequently causes neutropenia (low white blood cell count), which increases susceptibility to infections, and carries a heightened risk of developing myelodysplastic syndrome (MDS) or leukemia. Other common features include short stature and metaphyseal chondrodysplasia, which affects bone growth.

How common is Shwachman-Diamond Syndrome and who is affected?

Shwachman-Diamond Syndrome is a very rare condition with an estimated prevalence between 1 in 76,000 and 1 in 200,000 individuals worldwide. It affects males and females equally, with no specific geographic predilection. Symptoms of Shwachman-Diamond Syndrome usually present in infancy or early childhood, often identified when a child fails to thrive or experiences chronic diarrhea due to pancreatic insufficiency.

What causes Shwachman-Diamond Syndrome?

Shwachman-Diamond Syndrome is an autosomal recessive disorder, meaning an affected individual must inherit a pathogenic variant in both copies of the SBDS gene. The primary mechanisms include:

• Ribosomal Dysfunction: Mutations in the SBDS gene disrupt the maturation of the 60S ribosomal subunit.


• Cell Cycle Regulation: Impaired ribosome assembly leads to cellular stress, particularly in rapidly dividing cells like those in the bone marrow.


• Genomic Instability: The underlying genetic defect contributes to the increased risk of hematologic malignancies.

How does Shwachman-Diamond Syndrome differ from other conditions?

While Shwachman-Diamond Syndrome shares features with Cystic Fibrosis (due to pancreatic issues) and various bone marrow failure syndromes, it is clinically distinct. Unlike Cystic Fibrosis, Shwachman-Diamond Syndrome patients typically do not have sweat chloride abnormalities. Diagnosis is confirmed through genetic testing, which differentiates it from other causes of childhood neutropenia and malabsorption.

Next steps

• Consult with a hematologist and gastroenterologist familiar with Shwachman-Diamond Syndrome.


• Undergo genetic testing to confirm the diagnosis and provide information for family planning.


• Join the DiseaseMaps.org community to connect with the 14 members currently sharing their experiences with Shwachman-Diamond Syndrome.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Shwachman-Diamond Syndrome


• Orphanet: Shwachman-Diamond Syndrome (ORPHA:3134)


• OMIM (Online Mendelian Inheritance in Man): #260400


• Shwachman-Diamond Syndrome Foundation