A rare autosomal recessive inherited disorder caused by mutations in the NGLY1 gene. It is characterized by developmental delay, hypotonia, abnormal involuntary movements, poor tear production, microcephaly, intractable seizures, abnormal eye movements, and liver abnormalities. The disease is MONDO_0800044 (congenital disorder of deglycosylation 1). Also known as: CDG1V, NGLY1 Deficiency, NGLY1 deficiency, NGLY1-CDDG, NGLY1-deficiency, NGLY1-related congenital disorder of deglycosylation, congenital disorder of glycosylation type IV, deficiency of N-glycanase 1.