A combination of two novels homozygous FCSK variants cause disorder of glycosylation with defective fucosylation: New patient and literature review

Pathogenic variants in FCSK cause Congenital Disorder of Glycosylation with Defective Fucosylation-2 (FCSK-CDG; MIM: 618,324). It is a rare autosomal recessive genetic disease caused by defects in the L-fucose kinase, which is necessary for the fucose salvage pathway. Herein, we report two novel variants in an Iranian patient, the fourth individual with FCSK-CDG described in the literature. […] The proband, a four-and-a-half year old Iranian male born to consanguineous parents, manifested Intellectual disability, growth delay, ophthalmic abnormalities, seizures, speech disorder, and feeding difficulties.