Congenital disorders of glycosylation form a rapidly growing group of inherited 
metabolic diseases. As glycosylation affects proteins all over the organism, a 
mutation in a single gene leads to a multisystemic disorder. We describe a 
patient with TMEM165-CDG with facial dysmorphism, nephrotic syndrome, cardiac 
defects, enlarged cerebral ventricles, feeding problems, and neurological 
involvement. Having confirmed the diagnosis via prenatal diagnostics, we were 
able to observe the glycosylation right from birth, finding a pathological 
pattern already on the first day of life. Within the next few weeks, 
hypoglycosylation progressed to less sialylated and then also to 
hypogalactosylated isoforms. On the whole, there has not been much published 
evidence concerning postnatal glycosylation and its adaptational process. This 
is the first paper reporting changes in glycosylation patterns over the first 
postnatal weeks in TMEM165-CDG.