<prompt> A 6-year-old boy presents with acute abdomen and nonhealing ulcer on medial malleolus. Peripheral smear is shown. The most likely cause of this condition is?Trinucleotide repeatAntibody to RBC membraneSubstitution of single amino acid baseGenomic imprinting  <response>: Ref: Robbins, 8th ed. pg. 645-647Point mutation in 6th codon of b-globin that leads to replacement of glutamate by valine residue. 