MR Imaging Findings in Xp21.2 Duplication Syndrome
Xp21.2 duplication syndrome is a rare genetic disorder of undetermined prevalence and clinical relevance. As the use of chromosomal microarray has become first line for the work-up of childhood developmental delay, more gene deletions and duplications have been recognized. To the best of our knowledge, the imaging findings of Xp21.2 duplication syndrome have not been reported. We report a case of a 33 month-old male referred for developmental delay that was found to have an Xp21.2 duplication containing the ILRAPL1 gene and multiple midline brain malformations. Sagittal T1WI demonstrate multiple midline malformations including hypothalamic union, corpus callosum dysgenesis, and hypoplasia of the fornices, anterior commissure, and inferior vermis (Figure 1). The pituitary gland, optic chiasm, and brainstem are normal. Coronal T2WI show failed hypothalamic separation across midline and underdevelopment of the inferior 3rd ventricle (Figure 2). Coronal T1WI and T2WI through the level of the cribriform plate demonstrate absent formation of the olfactory sulci and olfactory bulbs, representing olfactory aplasia or severe hypoplasia (Figures 3 and 4). No additional structural abnormality is present. The hippocampi are normal.