Increasing severity of mental retardation of male members over generations is a result of -: (A) Mitochondrial DNA mutation, (B) Frameshift mutation, (C) Y linked disorder, (D) Trinucleotide repeat mutation
Answer is D. Ans. (d) Trinucleotide repeat mutation(Ref: Robbins 9th/pg 168-171; 8th/pg 168-171)Increasing severity of mental retardation of male members over generations is a result of "anticipation", seen in disorders caused by Trinucleotide repeat mutation. Eg Fragile X syndrome