Table 1. Imaging genetic studies in DD.
| Locus | Location | Gene | Function | Reliability | Imaging | Results |
|---|---|---|---|---|---|---|
| DYX1 | 15q21 | DYX1C1 | Neuronal migration, estrogen receptor transport, and cilia structure and function | Ten independent samples (Finnish, British, two Italian, German, Canadian, Australian, American, Indian, Chinese) | Structural | rs3743205 is significantly correlated with the inferior cerebellar network in both subjects with SKZ and in controls; the magnitude of the relationship did not differ between groups. On the contrary, the gender-matched subsample showed a stronger correlation in subjects with SKZ compared with controls (Jamadar et al.201) rs3743204 is significantly associated with WM volume of the temporo-parietal region containing WM pathways connecting the MTG with the inferior parietal lobe, that is, the SLF and the posterior part of CC (Darki et al.203, 204) |
| DYX2 | 6p22.3-p21.3 | DCDC2 | Neurite outgrowth, neuronal migration and ciliary functions | Ten independent samples (two American, two British, German, Australian, Canadian, Italian, Chinese, Indian) | Structural | rs793842 is significantly associated with WM volume of the temporo-parietal region containing WM pathways connecting the MTG with the inferior parietal lobe, that is, the SLF and the posterior part of CC (Darki et al.203, 204) rs793842 is significantly associated with the thickness of left AG and SG as well as the left LOC (Darki et al.204) rs1087266 is significantly correlated with the superior prefrontal, occipital and temporal networks in subjects with SKZ but not in controls. rs793862 is significantly correlated with the superior cerebellar network in both subjects with SKZ and in controls; the magnitude of the relationship did not differ between groups. On the contrary, in the gender-matched subsample the correlation in subjects with SKZ do not reach significance while it is significant in controls (Jamadar et al.201) DCDC2d is significantly correlated with higher GM volumes in left TG, FG, H/PHG, IOPG, IFG, and IMG (Meda et al.200) DCDC2d is associated with FA decreases in the bilateral ILF and in the genu of the CC in subjects with DD, and with FA reductions in the genu of the CC bilaterally and in the body of the CC in the right hemisphere, in the left ILF, AF and IFOF, and in the right IFOF, and in the body and splenium of CC in controls (Marino et al.207) |
| Functional | rs1087266 and rs793862 significantly correlate with Broca-Medial-Parietal network in both subjects with SKZ and controls (Jamadar et al.202) During PC, BV677278 complex tandem repeat is associated with left AIPL and right LOTG. During AC, BV677278 complex tandem repeat is associated with right LOTG. During reading tasks, BV677278 complex tandem repeat is nominally associated with the SACG, PCG, left PCL and IFG, and rs2143340 with the bilateral AIPL (Cope et al.199) | |||||
| KIAA0319 | Neuronal migration and ciliary functions | Structural | rs4504469 is significantly correlated with the superior cerebellar network in both subjects with SKZ and in controls; the magnitude of the relationship did not differ between groups. On the contrary, in the gender-matched subsample the correlation in subjects with SKZ do not reach significance while it is significant in controls (Jamadar et al.201) rs6935076 is significantly associated with WM volume of the temporo-parietal region containing WM pathways connecting the MTG with the inferior parietal lobe, that is, the SLF and the posterior part of CC (Darki et al.203, 204) rs9461045 is associated with cortical thickness in the left orbitofrontal region and FA in the CC (Eicher et al.208) | |||
| Functional | rs17243157 is associated with asymmetry in functional activation of the STS (Pinel et al.205) rs2038136 and rs2038137 significantly correlate with the left Broca-superior/inferior parietal network in controls, and with the left Wernicke-fronto-occipital network in both subjects with SKZ and controls. rs4504469 is significantly correlated with the bilateral Wernicke-fronto-parietal network in controls (Jamadar et al.202) | |||||
| DYX3 | 2p16-p15 | MRPL19 and C2ORF3 | rRNA processing | Two independent samples (Finnish and German) | Structural | rs917235 is significantly associated with WM structure in the posterior part of the CC and cingulum, connecting large parts of the cortex in the parietal, occipital and temporal lobes (Scerri et al.206) rs917235 and rs6732511 show suggestive association with cortical thickness in the left middle temporal region and cortical volume in the right fusiform region, respectively. rs2298248 is associated with cortical thickness in the right middle temporal region and with cortical volume in the right inferior temporal region (Eicher et al.208). |
| DYX4 | 6q11.2-q12 | — | — | — | — | — |
| DYX5 | 3p12-q13 | ROBO1 | Axon guidance receptor regulating the connections between brain hemispheres | Four independent samples (Finnish, Australian, Italian, Indian) | — | — |
| DYX6 | 18p11.2 | MC5R, DYM, NEDD4L | — | — | — | — |
| DYX7 | 11p15.5 | — | — | — | — | — |
| DYX8 | 1p36-p34 | KIAA0319L | — | — | — | |
| DYX9 | Xq27.2-q28 | — | — | — | — | — |
| No locus named | 12p13.1 | GRIN2B | Neuronal pattern formation, channel function and formation of dendritic spines in hippocampal pyramidal cells | Two independent samples (German and Italian) | Functional | rs2160517, rs219931, rs11055792, rs17833967 and rs12814951 are associated with the dorsolateral prefrontal cortex activity during a working memory tasks (Pergola et al.209) |
| No locus named | 7q31 | FOXP2 | Neurite growth and branching, transcriptional regulation | Two independent samples (American and German) | Functional | rs6980093 is associated with higher levels of activation in the bilateral IFG during both reading and speech listening tasks (Pinel et al.205) rs12533005 modulates the activation in occipital and inferior temporal brain areas, the AG, the insula and inferior frontal brain areas, during phonological and visual processing tasks (Wilcke et al.17) |
| No locus named | 7q35 | CNTNAP2 | Neuronal connectivity at the cellular and network level, interneuron development/function, synaptic organization and activity, migration of neurons | Two independent samples (British and German) | Structural | rs7794745 is associated with altered structural brain connectivity in a general population sample (Dennis et al.211) and with reduction in GM and WM volume and FA in the cerebellum, FG, occipital and frontal cortices in subjects with ASD (Tan et al.214) rs2710126 is associated with FA in the uncinate fasciculus in subjects with SKZ (von Hohenberg et al.213) |
| Functional | rs2710102 is associated with modulation of frontal lobar connectivity in subjects with ASD autism spectrum disorder (Scott Van-Zeeland et al.215), and with increased brain activation in BA7, BA44 and BA21 during a language processing task in healthy individuals (Whalley et al.212) rs7794745 is associated with brain activation in BA7, BA44 and BA21 during a language processing task in healthy individuals (Whalley et al.212) |
Abbreviations: AC, auditory categorization; AF, arcuate fasciculus; AG, angular gyrus; AIPL, anterior inferior parietal lobe; ASD, autism spectrum disorder; BA, Brodman's area; CC, corpus callosum; DCDC2d, deletion in intron 2 of the DCDC2 gene; DD, developmental dyslexia; FA, fractional anisotropy; FG, fusiform gyrus; GM, gray matter; H/PHG, hippocampal/parahippocampal gyrus; IFG, inferior frontal gyrus; IFOF, inferior fronto-occipital fasciculus; ILF, inferior longitudinal fasciculus; IMG, inferior medial gyrus; IOPG, inferior occipito-parietal gyrus; LOC, lateral occipital cortex; LOTG, lateral occipital temporal gyrus; MTG, middle temporal gyrus; PC, print categorization; PCG, posterior cingulate gyrus; PCL, paracentral lobule; SACG, superior anterior cingulate gyrus; SG, supramarginal gyrus; SKZ, schizophrenia; SLF, superior longitudinal fasciculus; STS, superior temporal sulcus; TG, temporal gyrus; WM, white matter.