Clinical and genetic features of pediatric acute lymphoblastic leukemia in Down syndrome in the Nordic countries

Table 1 Clinical features of the 128 DS-ALL and the 4,637 non-DS-ALL patients

Features	DS-ALL (%)	non-DS-ALL (%)	P value^a
Gender
Female	63 (49)	2195 (47)	0.67^b
Male	65 (51)	2442 (53)
Age (years)
<1	0 (0)	154 (3.3)	0.029 ^c
1-9	95 (74)	3703 (80)
10-17	33 (26)	780 (17)
WBC count (×10 ⁹ /l)
0-9	61 (48)	2408 (52)	0.51^c
10-49	50 (39)	1453 (31)
>50	17 (13)	776 (17)
Platelet count (×10 ⁹ /l) ^d
<50	76 (59)	2310 (50)	0.005 ^c
50-149	41 (32)	1473 (32)
>150	6 (5)	755 (16)
EMD ^e
CNS	5^f (3.9)	125 (2.7)	NA
Mediastinal	4^f (3.1)	72 (1.6)
Testis	0 (0)	15 (0.6)

CNS, central nervous system; DS-ALL, Down syndrome-related acute lymphoblastic leukemia; EMD, extramedullary disease; NA, not analyzed due to lack of EMD data in several instances; WBC, white blood cell.
^aSignificant P values in bold type.
^bChi square test.
^cMann-Whitney U test.
^dData on platelet counts missing in 5 DS-ALL and in 99 non-DS-ALL patients.
^eData on CNS involvement missing in 16 non-DS-ALL patients, on mediastinal mass in one DS-ALL and in 51 non-DS-ALL patients, and on testicular involvement in 27 DS-ALL and in 990 non-DS-ALL patients.
^fOne patient had CNS involvement as well as a mediastinal mass.

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