NCI Definition: A subtype of myelodysplastic syndrome which initially lacks findings appropriate for classification into any other myelodysplastic category. There are no specific morphologic findings. The diagnosis can be made in the following instances: 1. in cases of refractory cytopenia with unilineage dysplasia or refractory cytopenia with multilineage dysplasia but with 1% blasts in the peripheral blood; 2: in cases of myelodysplastic syndrome with unilineage dysplasia which are associated with pancytopenia; 3: in cases with persistent cytopenia (s) with 1% or fewer blasts in the blood and fewer than 5% in the bone marrow, unequivocal dysplasia in less than 10% of the cells in one or more myeloid lineages, and cytogenetic abnormalities considered as presumptive evidence of myelodysplastic syndrome. (WHO, 2008) [1]

Myelodysplastic syndrome, unclassifiables most frequently harbor alterations in PTPN11, ASXL1, WT1, U2AF1, and TET2 [2].

Most Commonly Altered Genes in Myelodysplastic Syndrome, Unclassifiable

PTPN11 Mutation, ASXL1fs, WT1fs, WT1 T377*, and WT1 Mutation are the most common alterations in myelodysplastic syndrome, unclassifiable [2].

Top Alterations in Myelodysplastic Syndrome, Unclassifiable

Disease Details

MDS, Unclassifiable, Unclassifiable MDS, Unclassifiable Myelodysplastic Syndrome, MDS, U, MDS-U
Myelodysplastic Syndromes
OncoTree Name
MDS, Unclassifiable
OncoTree Code


1. National Cancer Institute. NCI Thesaurus Version 18.11d. https://ncit.nci.nih.gov/ncitbrowser/ [2018-08-28]. [2018-09-21].

2. The AACR Project GENIE Consortium. AACR Project GENIE: powering precision medicine through an international consortium. Cancer Discovery. 2017;7(8):818-831. Dataset Version 8. This dataset does not represent the totality of the genetic landscape; see paper for more information.

3. All assertions and clinical trial landscape data are curated from primary sources. You can read more about the curation process here.