[Clinical features and gene mutations of children with Shwachman-Diamond syndrome and malignant myeloid transformation].

OBJECTIVE

To study the clinical features and genetic mutations of children with Shwachman-Diamond syndrome (SDS) and malignant myeloid transformation.

METHODS

Next-generation sequencing was used to analyze the gene mutations in 11 SDS children with malignant myeloid transformation, and their clinical features and genetic mutations were analyzed.

RESULTS

Of the 11 children with SDS, 9 (82%) presented with refractory cytopenia of childhood (RCC), 1 (9%) had myelodysplastic syndrome with excess blasts (MDS-EB), and 1 (9%) had acute myeloid leukemia with myelodysplasia-related changes (AML-MRC). The median age of onset of malignant myeloid transformation was 48 months (ranged 7 months to 14 years). Of the 11 children, 45% had abnormalities in the hematological system alone. Mutations of the SBDS gene were detected in all 11 children, among whom 5 (45%) had c.258+2T>C homozygous mutation and 3 (27%) had c.184A>T+c.258+2T>C compound heterozygous mutation. The new mutations of the SBDS gene, c.634_635insAACATACCTGT+c.637_638delGA and c.8T>C, were rated as "pathogenic" and "possibly pathogenic" respectively. The 3-year predicted overall survival rates of children transformed to RCC and MDS-EB/AML-MRC were 100% and 0% respectively (P=0.001).

CONCLUSIONS

SDS children may have hematological system symptoms as the only manifestation, which needs to be taken seriously in clinical practice. The type of malignant transformation is associated with prognosis.