Conclusions

We report a case of a five-year-old girl with syntelencephaly characterized by fusion of the cerebral hemispheres at the posterior parts of the frontal lobes and anterior parts of the parietal lobes, hypoplasia of the corpus callosum, heterotopic gray matter, an azygos anterior cerebral artery, and absence of the septum pellucidum. Our patient also met the diagnostic criteria for septo-optic dysplasia, with bilateral optic nerve hypoplasia and diabetes insipidus. We propose that this co-occurrence may reflect a shared disruption of midline forebrain development during a common window of early gestation, though causality cannot be established from a single case. Recognition of both the typical and atypical manifestations of syntelencephaly, including its potential association with septo-optic dysplasia, may facilitate earlier diagnosis, prompt evaluation for associated endocrine and ophthalmologic abnormalities, and encourage appropriate multidisciplinary management.