KIF16B is a candidate gene for a novel autosomal-recessive intellectual disability syndrome

Intellectual disability (ID) and global developmental delay are closely related; the latter is reserved for children under the age of 5 years as it is challenging to reliably assess clinical severity in this population. ID is a common condition, with up to 1%-3% of the population being affected and leading to a huge social and economic impact. ID is attributed to genetic abnormalities most of the time; however, the exact role of genetic involvement in ID is yet to be determined. Whole exome sequencing (WES) has gained popularity in the workup for ID, and multiple studies have been published examining the diagnostic yield in identification of the disease-causing variant (16%-55%), with the genetic involvement increasing as intelligence quotient decreases. WES has also accelerated novel disease gene discovery in this field. We identified a novel biallelic variant in the KIF16B gene (NM_024704.4:c.3611T>G) in two brothers that may be the cause of their phenotype.