Phenotypic variability in two siblings with Poretti-Boltshauser syndrome

Introduction: gene, resulting in cerebellar abnormalities, including cerebellar cysts in most cases. Case presentation: mutations and distinct phenotypic presentation, with one of them showing no evidence of cerebellar cysts on magnetic resonance imaging (MRI). Conclusion: This study highlights intrafamilial variability in patients with Poretti-Boltshauser Syndrome (PBS). Patient 1 exhibits more pronounced cerebellar dysplasia (with cysts) and oculomotor apraxia, while Patient 2 shows milder cerebellar dysplasia (without cysts) and a macular hole. These findings underscore the importance of comprehensive evaluation and genetic testing for accurate diagnosis and management of PBS.