Table 1.
Alterations of GABAergic signaling in patients with idiopathic forms of autism and Rett syndrome.
| Clinical phenotype | Alterations of GABAergic signaling | Age (years) | Reference |
|---|---|---|---|
| GENETIC OBSERVATIONS | |||
| Idiopathic autism | Linkage disequilibrium in GABRB3 | 7.6 ± 6.2 | (36, 37) |
| Idiopathic autism | Altered gene expression in interneurons | Not specified | (38) |
| IN VITRO ANALYSIS OF POST-MORTEM BRAIN TISSUES | |||
| Idiopathic autism | Reduction in the density of GABAA, GABAB receptors and benzodiazepine binding sites in the anterior cingulate cortex | 19/43 | (39) |
| Idiopathic autism | Reduction in the density of GABAB receptors cingulate cortex and fusiform gyrus | 19/43 | (40) |
| Idiopathic autism | Reduction in 3[H]flunitrazepam labeled benzodiazepines binding sites in the hippocampus | 16/22 | (41) |
| Idiopathic autism | Decreased number of GABAergic Purkinje cells in cerebellum | 13/54 | (42) |
| Idiopathic autism | Reduced level of GAD65 and GAD67 in Purkinje cells of cerebellar and parietal cortices | 19/30 | (43) |
| Idiopathic autism | Decreased GAD67 mRNA levels in cerebellar Purkinje cells | 16/30 | (44) |
| Idiopathic autism | Decreased GAD65 mRNA levels in cerebellar dentate nuclei | 16/30 | (45) |
| Idiopathic autism | Increased expression of GABAergic interneurons expressing calcium-binding proteins in the hippocampus | 13/63 | (46) |
| Rett syndrome | Disruption in the inhibitory architecture of the cell mini-columns | 14.4 ± 4 | (47) |
| IN VIVO STUDIES | |||
| Idiopathic autism | Reduction of GABA concentration in the frontal lobe | 2/12 | (48) |
| Idiopathic autism | Reduced GABA levels in the perisylvian region of the left hemisphere | 12.4 ± 5.2 | (49) |
| Idiopathic autism | Reduced expression of GABAA receptors in the superior and medial frontal cortex | 7.3 ± 3.5 | (50) |
| Rett syndrome | Reduced GABAA receptor density in fronto-temporal cortex | 27/41 | (51) |
| Idiopathic autism | Significant reduction of α5 GABAA receptor subunits in limbic areas | 34/43 | (52) |
| Rett syndrome | Reduced KCC2/NKCC1 ratio in the cerebrospinal fluid | 0/19 | (53) |
Numbers refer to mean (usually ± SEM) or range values.