If genes were the only factors in the syndrome, then the twins would be expected to have identical symptoms, since identical twins supposedly have identical genes.
(genes; were; the only factors in the syndrome) (the twins; would be expected; since identical twins supposedly have identical genes; T:then) (the twins; to have; identical symptoms) (identical twins; supposedly have; identical genes)
genes the twins the twins identical twins
were would be expected to have supposedly have
the only factors in the syndrome
since identical twins supposedly have identical genes T:then
identical symptoms
identical genes