Linkage studies are summarized in Table 3. Results are reported as a logarithm of the odds (LOD) score, rather than a p value. The majority of the studies reported in Table 3 used an affected sibling design (in which two siblings have MD). In this design, an LOD score of 2.2 is suggestive evidence for linkage (expected to occur once by chance in a genome scan), an LOD score greater than 3.6 represents significant linkage (expected to occur by chance with a probability of 5%), and an LOD score of 5.4 is highly significant (probability of chance occurrence is less than 0.1%) (Lander and Kruglyak, 1995).Table 3Linkage StudiesPhenotypeStudy NameFamiliesIndividuals%FClinical InstrumentPeak MarkerPeak LOD ScoreMarker LocationSexZubenko et al., 2003RMD 375 pairs; MD 520 pairs; mood disorder 610 pairs; depression spectrum 520Pittsburgh families811,24251.63SADS-LD1S15973.6chr1:13,684,108-13,884,418–RMD 375 pairs; MD 520 pairs; mood disorder 610 pairs; depression spectrum 520Pittsburgh families811,24251.63SADS-LD1S16092.7chr1:243,965,857-244,166,112–RMD 375 pairs; MD 520 pairs; mood disorder 610 pairs; depression spectrum 520Pittsburgh families811,24251.63SADS-LD2S4272.77chr2:232,106,263-232,306,614–RMD 375 pairs; MD 520 pairs; mood disorder 610 pairs; depression spectrum 520Pittsburgh families811,24251.63SADS-LD5S15033.32chr5:98,071,660-98,272,056–RMD 375 pairs; MD 520 pairs; mood disorder 610 pairs; depression spectrum
