  We prove that $\beta_p(I(G)) = \beta_{p,p+r}(I(G))$ for skew Ferrers graph
$G$, where $p:=\pd(I(G))$ and $r:=\reg(I(G))$. As a consequence, we confirm
that Ene, Herzog and Hibi's conjecture is true for the Betti numbers in the
last columm of Betti table. We also give an explicit formula for the unique
extremal Betti number of binomial edge ideal for some closed graphs.
