A congenital disorder of glycosylation I that is characterized by poorly coordinated suck resulting in difficulty feeding and failure to thrive, myoclonic jerks with hypotonia and brisk reflexes progressing to a seizure disorder, roving eyes, developmental delay, poor to absent visual contact, and sensorineural hearing loss and has_material_basis_in homozygous or compound heterozygous mutation in the RFT1 gene on chromosome 3p21.