HSPD1 and inborn mitochondrial metabolism disorder: Pathogenic mutation of HSPD1 contributes to the onset of two distinct mitochondrial diseases: autosomal dominant spastic paraplegia 13 (SPG13, MIM #605280) [27,111] and autosomal recessive hypomyelinating leukodystrophy 4 (HLD4, MIM #612233) [28].