A genetic disorder is inherited as an autosomal recessive trait and represents a classic example of a point mutation. Its mutant allele exhibits pleiotropy by altering the shape of red blood cells under certain conditions, leading to multiple phenotypic effects. Which of the following describes the specific molecular basis of this disorder?

Step-by-step solution

The traits described in the question (autosomal recessive inheritance, point mutation, and pleiotropy affecting red blood cell shape) point to Sickle-cell anaemia. The molecular cause of Sickle-cell anaemia is the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta-globin chain of the haemoglobin molecule. This is due to a single base substitution at the sixth codon of the beta-globin gene from GAG to GUG. Option 1 is incorrect because it reverses the actual amino acid substitution