Table 2.
Systematic Screening of All Carriers of Reduced Penetrance (RP) Alleles in the UBC HD Biobank (n = 95) Reveals that the LOI Variant Is Enriched in Individuals Who Manifest with Huntington Disease (HD) in This Repeat Range
|
Clinically Manifest |
No Signs of Symptoms of HD |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| RP CAG Size | Expected AOO | LOI Carriers | Non-LOI Carriers | Total Screened | LOI Carrier Frequency | AOO Range | LOI Carriers | Non-LOI Carriers | Total Screened | LOI Carrier Frequency | Age Range |
| CAG 36 | 95 | 3 | 0 | 3 | 100% | 65–77 | 2 | 10 | 12 | 16.7% | 9–85 |
| CAG 37 | 85 | 6 | 0 | 6 | 100% | 44–60 | 0 | 2 | 2 | 0.0% | 28–73 |
| CAG 38 | 77 | 2 | 6 | 8 | 25.0% | 42–45 | 0 | 16 | 16 | 0.0% | 19–85 |
| CAG 39 | 69 | 1 | 18 | 19 | 5.3% | 43 | 1a | 28 | 29 | 3.4% | 22–79 |
| All RPs | NA | 12 | 24 | 36 | 33.3% | 42–77 | 3 | 56 | 59 | 5.1% | 9–85 |
The LOI variant is particularly relevant for individuals carrying RP alleles with fewer than 39 CAG repeats. Abbreviations: AOO, age of onset; LOI, loss of interruption; NA, not applicable; RP, reduced penetrance.
a
Carrier of an LOI allele where only the penultimate CAA is changed to CAG and CCA codon is unaltered: i.e., CAG(39)-CAG-CAG-CCG-CCA-CCG(10).