Dominant character in tomato is

$A$ : Myotonic dystrophy is caused by recessive mutant pleiotropic gene.
$R$ : Gene mutation leads to more synthesis of fibrillin proteins.

A hereditary disease, which is never passed on from father to son is

Loss of a $X$ chromosome in a particular cell during its development, results into

An abnormal human baby with $‘XXX’$ sex chromosomes was born due to