A family is afflicted with a form of degenerative muscle disease. All members of the family represented by the pedigree have undergone PCR-based DNA testing, as shown. Based upon the results of the assay, which of the following is the most likely molecular cause of the disease in this family? (PCR banding pattern shows increasing band size in affected individuals across generations)

1. A)Variable expressivity
2. B)Allelic heterogeneity
3. C)Meiotic nondisjunction
4. D)Microsatellite instability
5. E)Trinucleotide repeat expansionGABARITO