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Table 2 Summary of genetic findings and muscle biopsy features in symptomatic carriers of DMD mutations

From: Prognostic value of X-chromosome inactivation in symptomatic female carriers of dystrophinopathy

Patient Phenotype DMD mutation Muscle biopsy features Dystrophin immunostaining Blood DNA XCI Muscle DNA XCI Most inactive
X-chr.
Origin of DMD mutation Familial skewed XCI
1 DMD-like Deletion exons 1–44 (c.(?_-244)_6438 + ?del, frameshift) Severe dystrophic pattern Generalized absence 93:7 n/p maternal paternal yes
2 DMD-like Subexonic deletion/insertion exon 17 (c.2095delinsTC, frameshift) End-stage muscular dystrophy n/p 100:0 51:49 paternal n/p no
3 D/BMD-like Stop exon 8 (c.724C > T, p.Gln242X) Severe dystrophic pattern Generalized absence 100:0 61:39 paternal n/p yes
4 Severe BMD-like Splice site exon 27 (c.3786 + 1G > A, predicted frameshift) Moderate dystrophic pattern Mosaic pattern 94:6 81:19 paternal maternal yes
5 Severe BMD-like Deletion exon 68 (c.9808-?_9974 + ?del, frameshift) Moderate dystrophic pattern Mosaic pattern 69:31 n/p maternal n/p yes
6 Severe BMD-like Stop exon 41 (c.5893C > T, p.Gln1965X) Severe dystrophic pattern Reduction/absence in isolated fibres 74:26 52:48 n/i n/p yes
7 Severe BMD-like Deletion exons 5–7 (c.265-?_649 + ?del, frameshift) Severe dystrophic pattern Mosaic pattern 81:19 87:12 n/p n/p n/p
8 Severe BMD-like Deletion exon 44 (c.6291-?_6438 + ?del, frameshift) Moderate dystrophic Mosaic pattern with predominance of negative fibres 100:0 n/p n/p n/p n/p
9 Mild BMD-like Deletion exons 43–45 (c.6118-?_6614 + ?del, frameshift) Mild dystrophic pattern Mosaic pattern n/i n/p n/p n/p n/p
10 Mild BMD-like Deletion exons 45–50 (c.6439-?_7309 + ?del, frameshift) Moderate dystrophic pattern. Mosaic pattern 71:29 n/p n/i maternal no
11 Mild BMD-like Deletion exons 53–54 (c.7661-?_8027 + ?del, frameshift) Mild dystrophic pattern Reduction/absence in isolated fibres 81:19 n/p n/i maternal no
12 Mild BMD-like Duplication exons 50–55 (c.7201-?_8217 + ?dup, predicted in-frame) n/p n/p n/i n/p n/p maternal n/p
13 Mild BMD-like Splice site exon 48 (c.6913-1G > A, frameshift) Mild dystrophic pattern Mosaic pattern 81:19 53:47 maternal maternal yes
14 Mild BMD-like Splice site exon 48 (c.6913-1G > A, frameshift) n/p n/p 72:28 n/p paternal maternal yes
15 Mild BMD-like Deletion exons 48–50 (c.6913-?_7309 + ?del, frameshift) Mild dystrophic pattern Mosaic pattern 52:48 40:60 n/p n/p n/p
16 DCM Deletion exon 44 (c.6291-?_6438 + ?del, frameshift) n/p n/p 99:1 n/p n/i n/p Yes
17 DCM Deletion exons 46–52 (c.6615-?_7660 + ?del, frameshift) n/p n/p 63:37 n/p n/p n/p n/p
18 Behavioural issues Duplication exons 13–27 (c.1483-?_3786 + ?dup, predicted in-frame) Myopathic changes Normal 99:1 97:3 paternal maternal Yes
19 MR Subexonic deletion exon 46 (c.6638delT, frameshift) Myopathic changes Absence in isolated fibres 88:12 69:31 paternal maternal yes
20 MR Deletion exons 46–55 (c.6615-?_8217 + ?del, frameshift) n/p n/p 100:0 n/p paternal maternal n/i
21 Myalgia Duplication exons 38–43 (c.5326-?_6290 + ?dup, predicted frameshift) n/p n/p 74:26 n/p paternal maternal yes
22 Myalgia Deletion exons 10–43 (c.961-?_6290 + ?del, frameshift) n/p n/p 51:49 n/p n/p n/p n/p
23 Myalgia Deletion exon 7 (c.531-?_649 + ?del, frameshift) Myopathic changes Reduction/absence in isolated fibres 78:22 n/p n/p n/p n/p
24 Myalgia Deletion exons 3–13 (c.94-?_1602 + ?del, in-frame) Myopathic changes Mosaic pattern 50:50 n/p n/p n/p n/p
  1. X-chromosome inactivation (XCI): skewed patterns >80:20 are in bold. n/p: not performed, n/i = non-informative AR alleles.