towards further assessment of data and better maintenance or prospects

for therapy.

http://dx.doi:10.1016/j.nmd.2014.06.222

G.P.181

Early onset and severe X-linked dilated cardiomyopathy with epilepsy,

behavioral abnormalities and elevated CK due to DMD gene intron 1 splice

site mutation

R. Ben Yaou 1, J.U.L. Nectoux 2, F.R.A. Iserin 3, S.A.L. Ould Amar 4,

N.O.R. Romero 1, S.H.A. Varnous 4, F.R.A. Leturcq 2, P.A.S. Laforet 1

1 Institut de myologie, APHP, GH Pitie Salpetriere, Paris,

France; 2 APHP, GH Cochin, Paris, France; 3 APHP, Hopital Necker-

Enfants Malades, Paris, France; 4 APHP, GH Pitie Salpetriere, Paris,

France

DMD gene mutations are responsible for the dystrophinopathies

including Duchenne and Becker muscular dystrophies (DMD/BMD).

Although usually associated with DMD and BMD, an almost exclusive

cardiac involvement was found in rare patients carrying DMD gene

mutations. We here report on a patient who developed dilated

cardiomyopathy since 11 years old and required heart transplantation at

14 years. An older brother was also affected and transplanted.

Moreover, the patient was treated by Risperidone and Lamotrigine for

behavioral abnormalities and generalized epilepsy. First neuromuscular

assessment at 24 years did not show any muscle weakness, atrophy or

hypertrophy, neither exercise intolerance nor rhabdomyolysis. CPK

levels were always high (from 300 to 14000 IU/L). Electromyographic

examination showed myopathic pattern with normal nerve conditions.

Muscle CT scan imaging was normal. As LMNA, MYH7 and LAMP2

genes analyses did not reveal any mutation, deltoid muscle biopsy was

performed and revealed fiber size variation, few centralized nuclei and

regenerating fibers without overt muscle fibrosis. Dystrophin protein

immunohistochemical studies showed irregular staining with DYS1,

MANDYS8, MANDRA1 antibodies while it was absent with DYS3

antibody. Moreover, muscle western blot studies showed highly reduced

amounts of dystrophin with normal molecular weight. Subsequent

DMD gene analysis did not found any genomic deletion or duplication.

However, dystrophin mRNA analysis showed no amplification for the

exon 1 to exon 6 fragment suggesting skipping of these exons. Finally,

DMD gene sequencing using next generation technologies lead to the

identification of an intron 1 splice donor site variation (c.31 + 4A > G).

This new case further illustrates the clinical heterogeneity of

dystrophinopathies. Additional molecular analyses are required to

decipher the molecular basis of the predominantly cardiac and central

nervous system involvement in this patient.

http://dx.doi:10.1016/j.nmd.2014.06.223

OUTCOME MEASURES

T.P.1

Pilot study evaluating motivation on the performance of timed walking in

boys with Duchenne muscular dystrophy

L.N. Alfano, L.P. Lowes, K.M. Berry, H. Yin, I. Dvorchik,

K.M. Flanigan, L. Cripe, J.R. Mendell

Nationwide Children’s Hospital, Columbus, USA

Current trials in Duchenne muscular dystrophy (DMD) have focused

on the distance traveled using the 6-min walk test (6MWT). As a primary

efficacy outcome for clinical trials it can be quantified over a continuous

scale. Limitations include a self-selected walking speed irrespective of

encouragement and weakness predisposing to falls. We predicted that a

monetary incentive of $50 could improve same-day 6MWT

performance. Nine DMD boys (mean age 7.7) were instructed to walk

quickly, not run. Encouragement was permitted throughout the test.

Subjects were then stratified into an above or below 350 m group and

randomly assigned to either the incentivized (IN) or non-incentivized

(non-IN) group. A second 6MWT was completed after a rest period

during which the following instructions were provided. The IN was told

“If you walk faster on this repeat 6MWT you will receive $50.

Remember to walk quickly and safely.” The non-IN were told “You are

repeating the 6MWT and remember to walk quickly and safely.” The

same evaluator conducted both tests, was blinded to group, and

provided the same encouragement during each 6MWT. Current data is

available in 9 boys, however data on a cohort of 36 will be presented.

The boys in the IN (n = 5, mean age = 7.7) walked an average of 44 m

(11%, max: 105 m) farther on the second 6MWT. The non-IN (n = 4,

mean age = 7.6) walked an average of 5.1 m (2%, max: 16 m) farther.

The increase in distance in IN was most distinct in the above 350 m

(75 m or 17%) compared to the below 350 m (24 m or 7%) group. Our

pilot data suggest that a financial incentive results in a measurable

increase in within-day 6MWT distance in DMD. This variance is more

pronounced in the above 350 m group which is the typical target for

clinical trials. This data suggests that external motivators have a

significant impact on the 6MWT and should be considered in the design

and interpretation of clinical trials.

http://dx.doi:10.1016/j.nmd.2014.06.224

T.P.2

The age of ambulation in boys with Duchenne muscular dystrophy and its use

as an end-point in clinical trials

J.J. Gissy 1, T. Johnson 1, D.J. Fox 2, A. Kumar 2, E. Ciafaloni 3, S. Kim 4,

M. Yang 5, A.J. van Essen 6, R.S. Finkel 7

1 University of Central Florida College of Medicine, Orlando, USA; 2 New

York State Dept of Health, Albany, USA; 3 University of Rochester School

of Medicine, Rochestrer, USA; 4 Centers for Disease Control, Atlanta,

USA; 5 Children’s Hospital Colorado, Aurora, USA; 6 University of

Groningen, Groningen, The Netherlands; 7 Nemours Children’s Hospital,

32827, USA

In preparation for a clinical trial to investigate the effectiveness of drug

treatment in infants with Duchenne MD, a clinically meaningful primary

outcome measure needs to be established. Our hypothesis is that infants

with DMD have delayed age to walking independently, have an innate

desire to walk as soon as the motor system permits this task, and that

an effective drug for DMD would reduce the age when independent

ambulation is reached. As such, age of independent ambulation is a

discrete dichotomous event that may serve as an effective primary

outcome measure in a clinical trial. The age when ambulation is first

achieved was studied in 2 DMD population samples: US CDC MD

STARnet (Dataset 1, 1982-present, n = 449) and a more historical

Dutch natural history survey (Dataset 2, 1961–1982, n = 473) and

compared to the WHO reference set in normal boys (mean ± SD

[months, m], where walking was achieved at 12.1 ± 1.8 m, 99% by

17.6 m. The data were not normally distributed, possibly due to recall

bias and rounding error. Age of ambulation in Dataset 1 was

17.0 ± 5 m and median age was 16.0 m, IQR 13.0, 18.0 with 96%

walking by 24 months. In dataset 2, the mean age of ambulation was

21.8 ± 7.1 m and median age of was 20.0 m, IQR 18.0, 24.0 with 81%

walking by 24 m. Based upon Data Set 1 there is a delay in walking

among DMD boys of mean 4.9 m. A clinical trial design, with 1:1

randomization, power of 90% and alpha of 0.05, for a drug that

shortens age at ambulation by 2 months, to a mean delay of 2.9 months,

would require 86 boys in each arm if the SD is 4 and 23 boys in each

860 Abstracts / Neuromuscular Disorders 24 (2014) 791–924