48, XXXY/49, XXXXY mosaic: new neuroradiological features in an ultra-rare syndrome

BACKGROUND Sex chromosomal aneuploidies in males are rare diseases with an overwhelming involvement of endocrinological and auxological issues; less frequently, other anomalies are observed. Neuroradiological issues are often not taken into account in single patients, and neuroradiological examinations are rarely performed. CASE PRESENTATION Here, we report a boy with 48,XXXY/49,XXXXY mosaicism, phenotypically characterized by hypotonia, intellectual disability, ventricular septal defect, micropenis, and with mild hypertelorism, inverted nipples, a congenital hip dysplasia, and some neuroradiological features so far not described. The Magnetic Resonance Imaging showed white matter abnormalities and enlargement of lateral ventricles with never described dysmorphisms of cranio-cervical junction and posterior fossa. A cranio-cervical Computerized Tomography confirmed a dysmorphic aspect of the posterior fossa and occipital condyles, slight morphological asymmetry of C1 and slight lateralization to the right of the odontoid's apex. CONCLUSIONS Considering the possible relevant clinical impact of these findings, the neuroradiological assessment seems potentially useful to the diagnostic approach of these patients.