A Newly Identified YIF1B Frameshift Variant Causing Kaya-Barakat-Masson Syndrome

Background Kaya-Barakat-Masson syndrome (KABAMAS) is a recently described autosomal recessive neurodevelopmental disorder caused by biallelic pathogenic variants in YIF1B , a gene crucial for trafficking between the endoplasmic reticulum and the Golgi apparatus. Disruption of this pathway leads to Golgi disorganization and neuronal dysfunction, resulting in severe developmental delay, visual impairment, and progressive spasticity. Case Presentation We report an 11-month-old Turkish girl with profound developmental delay, absent head control, poor feeding, laryngomalacia and cortical visual impairment. Brain magnetic resonance imaging (MRI) revealed corpus callosum thinning and mild ventriculomegaly. Comprehensive metabolic investigations were unrevealing. Whole exome sequencing analysis identified a novel homozygous YIF1B frameshift variant, c.440_441delinsA (p.Ala147Aspfs*51), predicted to cause loss of function. Conclusion This case broadens the mutational spectrum of YIF1B -related disease and highlights the distinctive clinical pattern of KABAMAS. Recognition of the combination of developmental delay, cortical visual loss, and normal metabolic studies should prompt early genetic analysis. Timely molecular diagnosis enables accurate counseling and multidisciplinary management for affected families.