This is not unique for CDG; for example, it is a rather frequent finding in Phosphomannomutase deficiency.5 Interesting is the presence of proteinuria without other symptoms in some carriers.There is some phenotypic overlap with defects in other vacuolar H+‐ATPase subunits: cutis laxa in ATP6V0A2‐CDG, ATP6V1A, ATP6V1E1 and ATP6AP2; liver disease in ATP6AP2‐CDG, CCDC115‐CDG and TMEM199‐CDG; and immunodeficiency in ATP6AP2.6, 7, 8, 9, 10, 11 In males with sensorineural deafness, hair loss and proteinuria, screening for CDG should be performed. The gene discussed is ATP6AP2; the disease is immunodeficiency disease.