This phenomenon, first described in the context of thrombocytopenia-absent radius (TAR) syndrome, has only rarely been invoked since, e.g., SNORD118-related cerebral microangiopathy leukoencephalopathy with calcifications and cysts [47], and TXNL4A-related Burn-McKeown syndrome [48]. This evidence concerns the gene SNORD118 and Leukoencephalopathy.