Treacher Collins syndrome is associated with mutations of POLR1C and POLR1D (OMIM 248390 and OMIM 613717), and hypomyelinating leukodystrophy is associated with mutations of POLR3A and POLR3B (OMIM 607694 and OMIM 614381). The gene discussed is POLR1C; the disease is Treacher-Collins syndrome.