Table 1. Association of eight rare missense variants in CHRNA4 with FTND.
| Variant | P-value | Effect | MAF (%) | Imp Inf | Position | Minor allele | Major allele | Coding effect |
|---|---|---|---|---|---|---|---|---|
| chr20:61451525:S | 0.37 | −0.71 | 0.017 | 0.88 | 61 451 525 | A | G | S561L |
| rs77345643 | 0.099 | 0.91 | 0.038 | 0.73 | 61 451 540 | A | G | P556L |
| rs55915440 | 0.48 | 0.063 | 1.378 | 0.96 | 61 451 855 | A | G | P451L |
| rs121912272 | 0.76 | −0.042 | 0.547 | 0.91 | 61 451 979 | T | C | V410I |
| rs56175056 | 1.2 × 10−4 | 0.85 | 0.237 | 0.99 | 61 452 201 | A | G | R336C |
| chr20:61457796:S | 0.15 | 0.41 | 0.127 | 0.96 | 61 457 796 | A | G | R120W |
| chr20:61457871:S | 0.68 | 0.28 | 0.05 | 0.44 | 61 457 871 | G | C | D95H |
| chr20:61461433:S | 0.013 | 0.61 | 0.61 | 0.97 | 61 461 433 | T | C | G47S |
Abbreviations: FTND, Fagerström Test of Nicotine Dependence; Imp, imputation; Inf, information; MAF, minor allele frequency.
Table 1 shows association results for non-synonymous variants in CHRNA4 identified by sequencing 2636 Icelanders and imputing their variants into 104,220 Icelanders for the FTND run as a quantitative trait using three categories (FTND 0–3=mild, FTND 4–6=moderate and FTND 7–10=severe). Shown are identity of variant (rs names where available), P-value of association, effect size, minor allele frequency in Iceland (in %), imputation information, position of each variant on chromosome 20 in build 36, identity of minor and major alleles, and the coding effect of the variant. The reported effect size is in FTND units, obtained by multiplying the effect size from analysis with 3.5, the difference between midpoints of adjacent categories.