Fig. 1
From: De novo missense variants in RAC3 cause a novel neurodevelopmental syndrome
Five individuals from four families with missense variants in RAC3, severe developmental disorders, and brain malformations. See text and Table 1 for details. Additional photographs of the affected individuals in families I, II, and IV are provided in the Supplemental file (Figures S2–S5). Photographs and brain magnetic resonance images (MRIs) for the proband in family III were not available for publication. He was described as having brachycephaly, hypertelorism, a broad philtrum, and ulnar deviation of wrist joints. In the proband in family I, (a) sagittal T1 weighted image at 4 days of age demonstrates lack of corpus callosum (open arrow), Probst bundles, and cingulate gyrus. (b) Unilateral marked ventriculomegaly of right posterior horn, trigone, and temporal horn are present on T2 weighted axial image. There is marked thinning of the right occipital cortex (black arrow) and medial bifrontal polymicrogyria (white arrow). (c) Coronal T2 weighted image confirms lack of corpus callosum (open arrow). In the proband in family II, (d) sagittal T1 weighted image demonstrates thinning of the corpus callosum (open arrow) and caudal displacement of the forniceal columns (arrow). (e) Axial T2 weighted image shows moderate ventriculomegaly with dehiscent septal leaflets. Only a septal remnant (black arrow) remains. (f) Coronal T2 weighted image again shows ventriculomegaly and incomplete hippocampal rotation. There is fusion of the forniceal columns in the midline (black arrow). For the affected individuals in family IV, (g) sagittal T1 weighted image and (i) T2 weighted image demonstrate a dysgenetic corpus callosum with thick genu (open arrows), absent isthmus, and tapered splenium. Additionally, there is a Chiari 1 malformation (arrow) and ballooning of the aqueduct of Sylvius in each patient. (h) Axial T2 weighted image reveals pointed anterior horns, a heterotopic nodule indenting the left posterior horn (arrow), and posterior positional plagiocephaly. (j) Axial T2 weighted image demonstrates ventriculomegaly with Sylvian fissure shunt, a heterotopic nodule indenting the right posterior horn (arrow), and posterior positional plagiocephaly.
