Table 2 Spectrums of deletions/duplications in dystrophin gene in our cohort

Deletions by MLPA

136/236 (57.6%)

Duplication by MLPA

13/236 (5.5%)

Negative for mPCR

105/236 (44.5%)

Negative for MLPA

87/236 (36.8%)#

Mutation detection Percentage by mPCR

131/236 (55.5%)

Precise diagnosis by mPCR

(Exact deletion boundaries accurately detected by mPCR)

100/236 (42.4%)

Mutation detection Percentage by MLPA

149/236 (63.1%)

Additional Cases detected by MLPA

18/236 (7.6%)

Type of Variation

Considering genetically confirmed cases (n = 149)

DMD (n = 138)

BMD (n = 11)

Deletions

125/138 (90.6%)

11 (100%)

Distal Deletions

92/125 (73.6%)

11 (100%)

Proximal Deletions

33/125 (26.4%)

Not identified

Variation hotspot for deletions

(exon 45–55) and (exon 6–15)

(exon 45–49)

Duplications

13/138 (9.4%)

Not identified

Distal Duplications

5/13 (38.5%)

Not identified

Proximal Duplications

8/13 (61.5%)

Not identified

Variation hotspot for duplications

(exon 6–10)

Not identified

Single exon deletions

28/138 (20.3%)

Not identified

Frequently deleted single exon

Exon 44−8/28 (28.6%)

Exon 51- 7/28 (25%)

N/A

Single exon duplications

5/138 (3.6%)

Not identified

Frequently duplicated single exon

Exon 6- 2/5 (40%)

Exon 49- 2/5 (40%)

N/A

Non-contiguous deletions

2/138 (1.4%)

Not identified

Non-contiguous duplications

2/138 (1.4%)

Not identified

All Out of frame variations

117/138 (84.7%)

(Deletions and duplications

out of frame)

0

All In frame variations

17/138 (12.3%)

(Deletions and duplications

in frame)

11 (100%)

(In frame deletions only. Duplications not identified)

In frame variation hotspot for DMD

(Exon 45–60)

N/A

Deletions following reading frame rule

110/117 (94.0%)

(Out of frame deletions)

11 (100%)

(In frame deletions)

Deletions not following reading frame rule

13/17 (76.5%)

(In frame deletions)

0

(Out of frame deletions)

Duplications following reading frame rule

7/117 (5.9%)

(Out of frame duplications)

Not identified

Duplications not following reading frame rule

4/17 (23.5%)

(In frame duplications)

Not identified

Development delay present with the DMD cases not following reading frame rule

Global development delay—15/17 (88.2%)

Of which,

Language delay—11/15 (73.3%)

Motor development delay- 13/15 (86.7%)

N/A

Familial cases

21/138 (15.2%)

4/11 (36%)

Familial cases with deletions

20/21 (95.2%)

4 (100%)

Familial cases with duplications

1/21 (4.8%)

0

Patients eligible for available exon skipping gene therapy

Total 82/138 (59.4%)

Exon 51 skipping- 30/82 (36.6%)

Exon 53 skipping- 19/82 (23.2%)

Exon 45 skipping- 19/82 (23.2%)

Exon 50 skipping- 9/82 (10.9%)

Exon 44 skipping- 5/82 (6.1%)

N/A