A 20-year-old G1P0 female is 30 weeks EGA and decreased feta…

A 20-year-old G1P0 female is 30 weeks EGA and decreased fetal movement is noted. Ultrasound identifies fetal hydrops. After evaluation, mom is found to have microcytic anemia. If the hydrops is caused by a hemoglobinopathy, the fetal abnormality is most likely: