Edward’s and Patau syndrome, both of which have more than a 90% mortality rate before 1 year of age. There are extremely rare cases of survival beyond childhood which is why I said almost always, but by and large these syndromes do not allow for survival to adulthood.

This is a very specific phenomenon though. 47 chromosomes are almost always incompatible with survival to adulthood unless the extra chromosome is a sex chromosome or a 21, and I don’t think monosomy of any of the autosomes is compatible with life.