Figure 4.
An HTT Interrupting Sequence Variant that Results in an Additional CAA-CAG Repeat Is Associated with a Later Age of Onset (AOO) in Individuals with Huntington Disease (HD)
(A) The reference HTT CAG-CCG interrupting sequence in relation to the (CAA-CAG)2 variant. Nucleotides encoding the glutamine (i.e., CAG/CAA) and proline (i.e., CCG/CCA) tracts are shaded.
(B) The (CAA-CAG)2 variant is associated with later AOO as determined by the AOO ratio in HD subjects compared to HD subjects with the reference interrupting sequence. (CAA-CAG)2 carriers present on average 4.2 years later than the majority of individuals with HD with the reference CAG repeat interruption.