Shwachman-Diamond syndrome (SDS)

SDS is often first suspected in a baby or young child. Common clues are fatty, foul-smelling stools, slow weight gain and low neutrophils, the white blood cells that help fight infection. The diagnosis rests on two findings together. The pancreas makes too few digestive enzymes, and the bone marrow makes too few blood cells. A genetic test can confirm it.

Pancreas testing usually starts with a stool test called fecal elastase. Blood tests for pancreatic enzymes (serum trypsinogen and isoamylase) may be added. An ultrasound, CT or MRI scan can show fat where normal pancreas tissue should be. Blood counts are checked, and a bone marrow sample (aspiration and biopsy) shows how the marrow is working. Special X-rays can look for bone changes.

Genetic testing looks for changes in SBDS and three other genes: DNAJC21, EFL1 and SRP54. About 9 in 10 people with SDS have changes in both copies of SBDS. Doctors also rule out cystic fibrosis, which can cause similar digestion problems. A sweat test helps tell the two apart. Some findings change over time, which can make SDS harder to spot. Neutrophil counts can go up and down. Pancreas problems often ease as children grow. Experts recommend care by a team of specialists.

Pancreatic enzyme replacement, nutrition assessment and vitamin support address digestion and growth. The need for enzymes can change and is reassessed with the care team. Infections are treated promptly; selected people with serious recurrent infections may receive G-CSF.

Long-term blood and marrow surveillance helps identify significant changes. Monitoring also considers liver health, growth, bones and development.

Allogeneic transplantation may be appropriate for severe marrow failure or concerning myelodysplastic or leukemic disease. Conditioning is adapted to the person’s organ function and disease status. Transplant can correct blood production but does not repair pancreatic dysfunction or every other manifestation.

Many children with SDS are cared for with enzyme capsules at meals, vitamins, nutrition support and regular checkups. Boston Children's Hospital notes that with current care, most children with SDS lead normal lives. They usually still need ongoing medicine and regular hospital visits.

The biggest long-term concern is the bone marrow. About 10 to 30 of every 100 people with SDS develop a marrow cancer: a myelodysplastic neoplasm (MDS) or acute myeloid leukemia (AML). The risk rises with age. MDS and AML in people with SDS are hard to treat. So experts advise blood counts at least every 3 to 6 months and a marrow check every 1 to 3 years. The goal is to catch changes early.

Timing shapes transplant results. In a U.S. registry study, transplant for marrow failure went much better than transplant after MDS or leukemia had developed.