Table 2

Genotype-phenotype correlations

Patient NoOnset (mean
or range)
SexClinical phenotypeMutation% mutant (mean)ConservationMorphologyRC deficiencyFamily historyHaplogroup affiliation according to ref 21
FMntW-C bpRRFCCOCICIIICIV
(A) Genotype-phenotype correlation in 65 patients with known pathogenic mtDNA mutations
Deletions (n=28) 57%: DC; 21%: 4216;
11%: 12308; 7%:
12705; 4%: 15904
1–915 y81KSSdel60+++++s
10–2323 y77CPEOdel60+++++s
2425 y10CPEOdels20+++++f
252 d01Pearsondel60++++++++s
2640 y01MMdel50++++++s
2742 y01MMdels40+++++++s
2820 y10MNGIEdels30++f
Known pathogenic tRNA mutations
tRNALeu(UUR)(n=23) For 3243 (n=22):
50%: 4216; 27%:
DC: 27%; 14%:
12308; 9%: 12705
29–4212 y410MELASA3243G62++++++1s 13f
4327 y01CPEOA3243G50+++f
44–4629 y12Diab/DfA3243G28+f
4740 y01Diab/MMA3243G65++++s
48–5028 y12MMA3243G80++++?
51?01MELAST3271C45++++?
tRNASer(UCN)
52–542 y–8 y21PME/Df7472insC100++++1s 2fVariable27
55–565 mth–14 y11PME/DfT7512C100+++++1s 1fVariable27
57–583 y–30 y11MMG7497A100++++++1s 1fVariable27
tRNALys
59–6111 y12MERRFA8344G60+++++++fDC: n=2; 4216: n=1
tRNAPhe
6226 y01MMT618C95++++++f
tRNAAsp/Thr
631 y01MM, CMPG5703A100++++s
A15923G100+
tRNACys
64 11 y 0 1 MEM/SSPEE T5814C 100 + + + f
tRNALeu(CUN)
65 8 m 0 1 MEM/GA I T12297C 100 + + s
F M nt W-C bp RRF CCO CI CIII CIV
(B) Genotype-phenotype correlations in 26 patients with novel mtDNA mutations
tRNAPhe DC+ 12308
66–6720 y11MMT629C100+++sNA
1423 y10CPEOA644G100++s+
tRNALeu(UUR)
6811 y01ATX, SHL, MM, RPA3274G40++++s
tRNAMet
69–7020 y20MMT4418C100+++sNADC+ 4216
12308var
7145 y10CPEOA4435G13++s+
728 y01CPEOT4452C100++sNA
738 y01MMT4454C100+sNA
tRNATrp
72T5553C100
tRNAAsn
7410 y10MMA5715G100+sNA
tRNACys
756 y10ATX, SHL,G5773A100+s+DC
RP, Df
7634 y01MMG5773A100+++++sNADC
tRNATyr
77Birth01Cong LAC5839T100++s+
78Birth10Cong LAA5843G100+s
tRNASer(UCN)
79Birth10MEMA7500G100+(+)+sNA
tRNALys
80–81Birth12MEM, MHA8343G100+++++++s+DC
tRNAHis
27C12153T100NA
8234 y10MMA12172G100++sNA
tRNAThr
83Birth01HepatG15894A100+++sNA
845 y10MEMG15897A100+++s+DC
8534 y10MMG15897A100+++sNA
866 y01MEMG15930A100+s+DC
87Birth10MMG15930A100+f+
88Birth10HepatG15930A30(+)+s+
89–904–7 y11MEMT15941C100(+)+1s 1f+DC + 12308
tRNAPro
9139 y10CPEOT15968C100+++sNA
  • F, female; M, male; %, % mutant mtDNA in skeletal muscle; conservation nt, W-C bp, conservation of the nucleotide and Watson-Crick base pair; RRF, ragged red fibres; CCO, cytochrome c oxidase negative fibres; C, complex; haplogroup, haplogroup affiliation; ATX, ataxia; Hepat, hepatopathy; RP, retinopathy; SHL, sensorineural hearing loss; y, year; d, day; mth, months; del, single deletion; dels, multiple deletions; ∼, no relevance; +, high residual activity of 85–95% of the lowest reference range; ++, residual activity of 50–85% of the lowest reference range; +++, severe deficiency with residual activities of <50% when compared to the lowest reference range; s, single; f, familial; var, variable; id, identical; NA, not analysed. Patients 64 and 65 are typed in italics as our data did not confirm primary pathogenic influence of the tRNA mutations.