Actually, that's wrong.
From a study by the University of Iowa on Van der Woude Syndrome (common form of cleft lip): "It turns out that identical twins who differ for a single genetic trait are quite common."
It seems that your own article contradicts its self, not to mention ANY cites and the vast number of genetic twin studies for autism, asthma, et al…that claim concordance of 100% is THE standard.
“However, with almost no exceptions, the DNA of monozygotic twins will be identical, making a genetic search much easier…However, with almost no exceptions, the DNA of monozygotic twins will be identical, making a genetic search much easier.”
In fact the proof of MZ is quite hard to obtain, how many placentas did the Brazilian twins have? How was Zygosity proven and that it was not commonly DZ? This article is an anomaly and probably commercially driven.