Table 2. Correlations of housekeeping gene mRNAs with brain weight.
| Spearman correlation with brain weight | Partial correlation with brain weight | |||
|---|---|---|---|---|
| In whole sample | In controls | Controlling for age | Controlling for sex | |
| Cerebellum | ||||
| β2M | +0.241** | +0.354* | +0.258** | +0.276*** |
| GAPDH | +0.126 | ND | ND | ND |
| GUSB | +0.061 | ND | ND | ND |
| TFRCa | −0.295*** | −0.385* | ND | ND |
| Geometric mean | +0.204* | ND | ND | ND |
| Hippocampus | ||||
| GAPDH | +0.274*** | +0.392* | +0.115 | +0.090 |
| TBP | +0.320*** | +0.481** | +0.324*** | +0.293** |
| TFRC | +0.163 | ND | ND | ND |
| Geometric mean | +0.306** | +0.423** | +0.284** | +0.271** |
| Anterior cingulate cortex | ||||
| β2M | −0.019 | ND | ND | ND |
| GAPDH | +0.132 | ND | ND | ND |
| GUSB | −0.036 | ND | ND | ND |
| TFRC | −0.004 | ND | ND | ND |
| Geometric mean | +0.055 | ND | ND | ND |
*
p<0.05
**
p<0.02
***
p<0.01. ND: not determined, since one or both Spearman correlations failed to meet criteria for significance (see text).
a
Inspection of data showed correlation was driven by one control subject, who had a TFRC mRNA value >3.S.D. above mean; omission of the subject abolished the correlations (both r<0.1, p>0.6).