Table 1: Historic record of JMML (previously named JCML or jCMML) twin cases.

JMML/JCML/(j)CMML MZ type Karyotype Twin_01 Karyotype Twin_02 Reference Comments
46,XY 46,XY;
at final stage of the disease Ph+
Arch. of disease in childhood, 1977, 52: 72-74 Both twins deceased after a similar course of the disease
(j)MML No Karyotypic marker No Karyotypic marker Cancer, 1984, 54: 675-686 Twin sister disease after a different course of disease
No data monozygotic type
46,XX 46,XX Cancer Genet Cytogenet 1989, 38: 205-213 Karyotypes of both twins evolved with hyperdiploid clones; Both twins deceased after a similar course of the disease
Monozygosity 98%
46,XY, -7, +mar 46,XY, -7, +mar Leukemia 1997, 11: 306-312 Both twins responded well to therapy
ND monozygotic type
46,XY, t(7;16)(p10;q10)* 46,XY, t(7;16)(p10;q10 BLOOD, 1995, 85: 1742-1750 Twin_01 deceased at 5 month after diagnosis Twin_02 is alive at 11 month after diagnosis**
JCML ND on twin type ND ND BJH, 1995.90: 353-357 In one twin B-lineage clonality was demonstrated
monochorionic- biamniotic
46,XX with
NRAS mutation
Free of disease Pediatric Blood Cancer 2008, 50: 665-667 Discordant JMML in two twins

+This twin pair was included here since the Ph+ karyotype was found only in the terminal phase of the disease and because it is the 'oldest' case reporting a twin pair with a myelomonocytic leukemia. *constitutional translocation also present in the father without hematologic abnormalities; ** alive at time of publication (1995);