Refers to a heterogeneous group of cases that are clinically diagnosed as Werner syndrome but that do not carry WRN gene mutations. Similar to classical Werner Syndrome caused by WRN mutations, patients generally exhibit an aged appearance and common age-related disorders at earlier ages compared to the general population. Compared to Werner Syndrome, it has an earlier age of onset (early 20s or earlier) and a more rapid rate of progression. [from
SNOMEDCT_US]