Table 1

 Age at diagnosis and at enrolment of the twins

No of pairsMonozygotic twinsDizygotic twins
Concordant (n = 17)Discordant (n = 6)Total (n = 23)Concordant (n = 5)Discordant (n = 45)Total (n = 50)
Mean age at diagnosis (y)
    Index twin10.36.99.44.69.48.9
    Co-twin11.312.1
Mean age at enrolment (y)2120.520.822.417.818.3