We present a case study detailing cognitive performance, functional neuroimaging, and effects of a hypothesis-driven treatment in a 10-year-old girl diagnosed with complete, isolated corpus callosum agenesis. Despite having average overall intellectual abilities, the girl exhibited profound surface dyslexia and dysgraphia. Spelling treatment significantly and persistently improved her spelling of trained irregular words, and this improvement generalized to reading accuracy and speed of trained words. Diffusion weighted imaging revealed strengthened intrahemispheric white matter connectivity of the left temporal cortex after treatment and identified interhemispheric connectivity between the occipital lobes, likely facilitated by a pathway crossing the midline via the posterior commissure. This case underlines the corpus callosum's critical role in lexical reading and writing. It demonstrates that spelling treatment may enhance interhemispheric connectivity in corpus callosum agenesis through alternative pathways, boosting the development of a more efficient functional organization of the visual word form area within the left temporo-occipital cortex.

The objective of this study was to record the clinical, neuro-radiological, and systemic features of patients with septo-optic dysplasia (SOD). A retrospective review of patients was conducted to identify patients with features consistent with SOD over a 6-year period, including optic nerve hypoplasia with agenesis of midline structures, along with an absent septum pellucidum and/or agenesis of the corpus callosum. Thirty-three patients were identified. The male to female ratio was 2:1, while the median age at diagnosis was 5 years (interquartile range = 10 years, range = 0-44 years). Optic nerve hypoplasia (ONH) was bilateral in 81.81% of cases (n = 27) and unilateral in 18.18% of cases (n = 6), with three cases in each eye. Developmental delay was documented in 24.2% (n = 8). The most frequent magnetic resonance imaging features that were consistent with SOD included: isolated absent septum pellucidum reported in 51.51% (n = 17); isolated corpus callosum agenesis in 33.33% (n = 11); and both absent septum pellucidum and corpus callosum agenesis in 15.15% (n = 5). Pituitary gland abnormalities, including pituitary hypoplasia in 9% (n = 3) or hypoplasia of pituitary infundibulum in 6% (n = 2) were less common. Pituitary hormonal abnormalities were present in 50% of the 10 tested patients (n = 5). Although bilateral ONH is more frequent, hypoplasia of just one optic nerve could be a presenting feature of SOD. Therefore, additional neuro-imaging is important for a diagnosis in cases of unilateral and bilateral ONH and a multidisciplinary approach is beneficial.

This long-term retrospective follow-up study aimed to address the knowledge gap between prenatal diagnosis of complete isolated Agenesis of Corpus Callosum (cACC) at fetal MRI and postnatal neurodevelopmental outcome to improve prenatal counseling for parents. Data on fetuses with isolated cACC from a single-center MRI database built up in two decades were considered. Detailed postnatal clinical, neuropsychological evaluations were performed and descriptions of available neuroradiological and genetic data were provided. Following a detailed neuropsychological evaluation and a long-term follow-up, the subsequent results emerged: 38 school-aged children (older than 6 years) of 50 (aged 2.5-15 years) showed normal intellectual functions (50%), intellectual disability (21%), and borderline intelligence quotient (29%). Deficits in motor functions (58%), executive functions (37%), language (61%), memory abilities (58%), and academic performances (53%) were found. Twenty-one percent of participants showed behavioral difficulties. Almost half of the participants underwent rehabilitation. Additional findings (21%) were detected at postnatal brain MRI, and a significant association between additional findings at postnatal imaging and abnormal neurodevelopmental outcome was observed. This study supports the view that children with prenatal diagnosis of isolated cACC may present with several degrees of neurologic and neuropsychological impairment which become more evident only in their second decade of life. Postnatal MRI and detailed genetic analysis may add crucial information to prenatal data and substantially influence final judgment on the outcome and orient clinical management and counseling.

Mowat-Wilson syndrome (MWS) is an autosomal dominant genetic disorder caused by ZEB2 gene mutations, manifesting with unique facial characteristics, moderate to severe intellectual problems, and congenital malformations as Hirschsprung disease, genital and ophthalmological anomalies, and congenital cardiac anomalies. Herein, a case of 1-year-old boy with isolated agenesis of corpus callosum (IACC) in the prenatal period is presented. He was admitted postnatally with Hirschsprung disease (HSCR), hypertelorism, uplifted earlobes, deeply set eyes, frontal bossing, oval-shaped nasal tip, ''M'' shaped upper lip, opened mouth and prominent chin, and developmental delay. Hence, MWS was primarily considered and confirmed by the ZEB2 gene mutation analysis. His karyotype was normal. He had a history of having a prenatally terminated brother with similar features. Antenatally detected IACC should prompt a detailed investigation including karyotype and microarray; even if they are normal then whole exome sequencing (WES) should be done.