A 6-year-old child presents with recurrent urinary tract infections and renal stones. CT scan reveals fusion of the lower poles of both kidneys with an isthmus crossing the midline. What is the embryologic reason for failure of normal kidney ascent in this condition?
A
Compression by superior mesenteric artery
B
Entrapment under inferior mesenteric artery
C
Failure of ureteric bud development
D
Defective metanephric blastema differentiation