Phenotypic variability in two siblings with Poretti-Boltshauser syndrome

Poretti-Boltshauser Syndrome (PBS) is a rare neuro-ophthalmological disorder with autosomal recessive inheritance. It is characterized by non-progressive cerebellar ataxia, delay in neuropsychomotor development, intellectual disability, and vision abnormalities. PBS is caused by mutations in the LAMA1 gene, resulting in cerebellar abnormalities, including cerebellar cysts in most cases.

We present two siblings with LAMA1 mutations and distinct phenotypic presentation, with one of them showing no evidence of cerebellar cysts on magnetic resonance imaging (MRI).

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.