Review Question - QID 109978

A 26-year-old G1P0 woman comes to her maternal and fetal medicine doctor at 15 weeks of gestation in order to be evaluated for fetal developmental abnormalities. Her family has a history of congenital disorders leading to difficulty walking so she was concerned about her child. Amniocentesis shows normal levels of all serum proteins and circulating factors. Despite this, the physician warns that there is a possibility that there may be a neural tube abnormality in this child even though the normal results make it less likely. If this child was born with a neural tube closure abnormality, which of the following findings would most likely be seen in the child?