Table 4.
Relative expression of candidate genes in monozygotic "concordant" twin pairs with differential language impairment (PPVT percentile scores) and in normal twins
| Candidate Gene | Genbank # | PPVT – 30/42* | PPVT – 0.1/1 | Discordant twins¥ | Normal twins |
| ASS | AA676405 | 0.03 (-0.26)# | -0.01 (-0.69) | 0.85 (1.47) | 0.24 (0.54) |
| CHL1 | H15267 | 1.83 (1.48) | 1.99 (1.29) | 0.56 (0.46) | 1.40 (1.45) |
| IL6ST | T61343 | 0.88 (1.33) | 0.28 (-0.26) | 0.59 (0.58) | 0.37 (0.23) |
| IL6ST | AA406546 | 1.02 (0.85) | 0.34 (-0.14) | 0.58 (0.61) | 0.43 (0.47) |
| DAPK1 | AI371096 | -0.56 (-0.92) | -0.49 (-1.05) | 0.62 (0.65) | -0.13 (-0.18) |
| FLAP | T49652 | 1.18 (1.20) | 0.28 (-0.25) | 0.79 (0.58) | -0.19 (-0.34) |
| ITGB7 | AI380522 | -1.12 (-1.13) | -0.20 (-0.92) | -0.56 (-0.76) | 0.15 (0.04) |
| EGR2 | AA446027 | -2.02 (-3.10) | -1.26 (-2.16) | -0.40 (-0.79) | -0.23 (-0.37) |
| ROBO1 | AA173755 | -0.13 (0.25) | 0.41 (-0.18) | -0.66 (-0.93) | -0.45 (-0.80) |
| 5-HTT¶ | BC069484 | NP¶ (-2.39) | NP (-0.42) | NP (-0.96) | NP (-0.02) |
*Values represent the mean log2(ratio) of gene expression from DNA microarray data from 2 sets of monozygotic autistic twins who both met criteria for autism by either ADOS or ADI-R diagnostic tests, but have differential language impairment as indicated by their respective PPVT percentile scores. Data from 2 separate dye-reversal microarray experiments were averaged for each twin set. For each pair of twins, microarray data from the twin with the lower PPVT score was used as the numerator in calculating the gene expression ratio. PPVT – 30/42 refers to the twin pair whose PPVT percentile scores are 30 and 42, while PPVT – 0.1/1 refers to the twin pair whose percentile scores are 0.1 and 1. Interestingly, the two sets of twins share the same mother. The PPVT- 30/42 set are Caucasian males, as are the 3 sets of discordant twins, while the more severely language-impaired twins (PPVT -0.1/1) are black, Latino males.
#Values in parentheses are mean log2(ratio) expression measures obtained by triplicate qPCR analyses.
¥Mean expression value across 3 sets of twins discordant for diagnosis of classic autism.
¶Not present (NP) on microarray