The pathogenicity of the large duplication in patient 4 was evaluated based on the size of the CNV as well as two genes, TMEM165 and POLR2B. Mutations in the TMEM165 gene cause congenital disorder of glycosylation, type IIk in which postnatal growth retardation is a common symptom [20]. The gene discussed is TMEM165; the disease is disorder of glycosylation.