Here, in related NER progerias (CH/XPA, XPCS/XPA, TTD/XPA, and CSB/XPA), we demonstrated that cell-autonomous proliferative defects as observed in two different primary cell types, fibroblasts and erythroblasts, are not an absolute prerequisite for postnatal growth retardation or progeria. Here, ERCC2 is linked to progeroid syndrome.