Table 1.
Clinical Features of Acute Leukemia in Down Syndrome (DS) and Non-DS Children
| DS-ALL | Non-DS-ALL | DS-AML | Non-DS AML | |
|---|---|---|---|---|
| Total % of cases | 2% | 98% | 15% | 85% |
| Age at diagnosis | Peak 2–5 years | Peak 2–7 years | <4 years | Peak: <1 year, and during adolescence |
| Major predisposing risk factors | None | None | Prior history of the transient myeloproliferative disorder (TMD) | None |
| Cytogenetic subgroups | Lower frequency of hyperdiploidy and TEL-AML1 | Hyperdiploidy (25%–30%) | >90% are AMkL (M7) | ∼10% AMkL |
| Occurrence of T-cell | t(12,21) (20%–25%) | |||
| ALL rare | t(1,19) (5%–6%) | |||
| t(4,11) (2%) | ||||
| Associated somatic gene mutation | JAK2 mutations (∼20%) | TEL-AML1 fusion protein | GATA1 mutations (uniform) | Wild-type GATA1 |
| E2A-PBX1 fusion protein | ||||
| AF4-ALL1/MLL/HRX fusion proteins | ||||
| Treatment toxicity | Excessive toxicity to methotrexate Inreased frequency of infections | Chemotherapy associated myelosuppression | Increased risk of anthracycline-related cardiotoxicity | Chemotherapy associated myelosuppression |
| Cure rates | ∼65% | 70%–85% | 80%–100% | 50% (<30% for AMkL cases) |