Table 4.
Complex III variants
| Disease/clinical features | Variant | Subunit | AA change | Agea | % VAF | Complex III | Reference | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Muscle | Blood | Fibroblasts | Other | Residual activity, % | Protein levels | ||||||
| MELAS | 14864T > C | MT-CYB | Cys40Arg | 15 yr | 39 | 32 | 42 | 57, urinary sediment | 72, muscle | (Emmanuele et al. 2013) | |
| Mitochondrial disease | 15150G > A | MT-CYB | Trp135X | 60 | 0 | 0, lymphocytes | 7, muscle 183, fibroblasts 56, lymphocytes |
↓ | (Legros et al. 2001) | ||
| Progressive EXIT | 15170G > A | MT-CYB | Gly142X | 40 yr | 99 | <1 | <1, lymphocytes | 10, muscle | (Bruno et al. 2003) | ||
| Mitochondrial disease | 15197T > C | MT-CYB | Ser151Pro | 80 | 0 | 0, lymphocytes | 17, muscleb 167, fibroblastsb 72, lymphocytesb |
↓ | (Legros et al. 2001) | ||
| Hypertrophic cardiomyopathy | 15243G > A | MT-CYB | Gly166Glu | 8 yr | 100 | 90, heart | 22, heartb | (Valnot et al. 1999) | |||
| Severe growth restriction | 15498G > A | MT-CYB | Gly251Asp | 3 yr | 100 | 100, lymphocytes | 36, fibroblasts 43, lymphocytes |
(Haut et al. 2004) | |||
| Asymptomatic | 15498G > A | MT-CYB | Gly251Asp | 100 | 100, lymphocytes | 36, fibroblasts 57, lymphocytes |
(Haut et al. 2004) | ||||
| Asymptomatic | 15498G > A | MT-CYB | Gly251Asp | 100, lymphocytes | 50, lymphocytes | (Haut et al. 2004) | |||||
| Deafness, EXIT, cognitive dysfunction, and growth restriction | 15579A > G | MT-CYB | Tyr278Cys | 19 yr | 88 | 15, leukocytes | 6, muscle | (Wibrand et al. 2001) | |||
| Mitochondrial encephalopathy | 15699G > C | MT-CYB | Arg318Pro | 38 yr | 88 | 16, urinary sediment13, lymphocytes14, hair shaft | 4, muscle | (Blakely et al. 2005b) | |||
| Neonatal polyvisceral failure | 15635T > C | MT-CYB | Ser297Pro | Newborn | 100 | 100 | 100, leukocytes 100, liver |
83, muscle 7, fibroblasts 66, liver |
(Fragaki et al. 2009) | ||
| Progressive EXIT, muscle cramps and lactic acidosis | 15800C > T | MT-CYB | Gln352X | 24 yr | 45 | <1, “others” | 27, muscle | (Lamantea et al. 2002) | |||
-
aAge of the patient at which the VAF and complex I activity were measured.
-
bNormalized to protein, not citrate synthase.
-
(AA) Amino acid; (VAF) variant allele frequency; (CYB) cytochrome b; (MELAS) mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes; and (EXIT) exercise intolerance.
