Epidemiology (MDS)
MDS is much rarer in children than in adults.
Annual incidence of 1.8 per million children aged between 0 - 14.
Incidence is changes in different countries - higher in Japan and lower in UK.
Many children have associated abnormalities
- Pre-existing bone marrow failure
- Congenital abnormalities
| Congenital Conditions | Congenital Bone marrow failure |
|
| Trisomy 21 - Down syndrome | Distinct entity | |
| Trisomy 8 mosaicism | ||
| Familial MDS | ||
| Acquired Conditions | Prior chemotherapy or radiation therapy |
|
| Aplastic anemia |
Congenital Bone Marrow Failure
- MDS occurs in up to 50% of patients with Fanconi anemia before they are 40 years old.
- Often associated with monosomy 7 and duplications of 1q.
- Survival of these patients improved significantly when granulocyte colony stimulating factor (G-CSF) was introduced.
- Roughly 10% of patients will develop MDS.
- Partial or complete loss of chromosome 7 found in over 50% of these patients
- MDS usually preceded by development of acquired mutations in G-CSF receptor gene.
- Yearly screening examination of bone marrow is recommended to look for MDS.
- MDS occurs in 10 - 25% of patients
- Often associated with chromosome 7 abnormalities.
Acquired Aplastic Anemia
- MDS occurs in 10 -15 % of patients with aplastic anemia not treated with BMT.
- Possibly related to prolonged therapy with G-CSF and cyclosporine.
Familial MDS
- Many families have been described with several members affected by MDS
- Tend to have monosomy 7 or deletion of 7q.
Therapy related MDS
Peak incidence is 4 - 5 years after primary malignancy therapy
Two different types of malignant transformation
1. Alkylating agent related MDS
- Latency 3 - 5 years
- cytogenetics show deletions or loss of whole chromosomes
2. Epipodophyllotoxin related MDS
- Acquired translocations involving chromosome 11q23
- short interval between primary treatment and AML - often only 1 - 2 years
- Associated with a genetic susceptibility
