Question to the Department of Health and Social Care:

To ask Her Majesty’s Government, further to the Written Answer by Earl Howe on 17 November (HL2642), whether they consider that any of the mitochondrial diseases listed in Annex D of the "Mitochondrial Donation" consultation document could ever arise from a nuclear gene defect; and if so, what is their assessment of the frequency with which it occurs and how that has been reflected when discussing mitochondrial diseases that may be candidates for pronuclear transfer or spindle-chromosomal complex transfer.

As stated in my Written Answer of 17 November 2014 (Official Report, col. WA59) the mitochondrial diseases listed in Annex D of the mitochondrial donation consultation document are diseases caused by an inherited mutation in mitochondrial DNA. As such, none of these diseases are caused by a nuclear gene defect. Mitochondrial disorders caused by a nuclear gene defect are distinct from those listed in Annex D.