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

Area of Science:

• Genetics
• Neuroscience
• Cell Biology

Background:

• Kaya-Barakat-Masson syndrome (KABAMAS) is an autosomal recessive neurodevelopmental disorder.
• It is caused by pathogenic variants in the YIF1B gene, essential for ER-Golgi trafficking.
• Disruption leads to Golgi disorganization, neuronal dysfunction, developmental delay, visual impairment, and spasticity.

Purpose of the Study:

• To report a novel YIF1B variant in a patient with KABAMAS.
• To broaden the understanding of the YIF1B mutational spectrum.
• To highlight the clinical features and diagnostic approach for KABAMAS.

Main Methods:

• Clinical case presentation of an 11-month-old Turkish girl.
• Brain MRI for neuroimaging assessment.
• Whole exome sequencing for genetic variant identification.

Main Results:

• The patient presented with profound developmental delay, absent head control, feeding difficulties, laryngomalacia, and cortical visual impairment.
• MRI showed corpus callosum thinning and mild ventriculomegaly.
• A novel homozygous YIF1B frameshift variant (c.440_441delinsA) was identified, predicted to cause loss of function.

Conclusions:

• This case expands the known YIF1B mutational spectrum for KABAMAS.
• The distinctive clinical pattern includes developmental delay, cortical visual loss, and normal metabolic studies.
• Early genetic analysis is crucial for diagnosis, counseling, and management.