FTSJ1 and X-linked intellectual disability: In humans, seven different alleles of the human TRM7 homolog FTSJ1 have been linked to non-syndromic X-linked intellectual disability (NSXLID) [30–34], and lymphoblastoid cell lines (LCLs) derived from patients with two different FTSJ1 alleles had tRNAPhe with undetectable levels of Cm32 and Gm34 [34].