Prenatal diagnosis of monozygotic twins with phenotypic differences in chromosome 17q12 deletion syndrome.

We present a case study highlighting prenatal ultrasound findings in monozygotic twins with chromosome 17q12 deletion syndrome. Fetus A exhibited bilateral fetal pyelectasis and talipes equinovarus, while fetus B showed hyperechogenic kidneys. Despite sharing the same de novo variant, the twins displayed distinct clinical phenotypes, suggesting the presence of non-genetic factors influencing the phenotypic variability of this syndrome. This case represents the first documented instance of prenatally identified identical twins affected by 17q12 deletion syndrome.