Longitudinal Study of the Natural History of Duchenne Muscular Dystrophy (DMD)

Phenotyping Study Aims

Aim 1: Longitudinally assess body function and body structure (impairment) through the
measurement of anthropometrics, muscle strength and pulmonary function in subjects with DMD
through the multicenter CINRG network.

Aim 2: Longitudinally assess activity limitations in subjects with DMD through CINRG with
timed motor performance, burden of care, and functional status.

Aim 3: Longitudinally assess secondary conditions in subjects with DMD, and relative risks
of developing those conditions based on exposure to preventive interventions.

Aim 4: Longitudinally assess participation, life satisfaction, service utilization and
health-related quality of life in subjects with DMD.

Aim 5: Determine appropriate outcome measurements for impairment, activities (activity
limitations), participation and quality of life to determine the effect of prednisone and
other therapeutic interventions on these factors.

Aim 6: Using the most robust impairment, activity, participation and quality of life outcome
measures, determine the sample size, power and statistical methods for the analysis of the
effect size for future planned randomized-controlled rehabilitation interventions in DMD.

Aim 7: Examine the associations between interventions and incidence and severity of
secondary conditions, achievement of disease milestones and measures of motor function and
mobility.

Aim 8: To assess the validity and responsiveness of novel clinical outcome measures in DMD,
including the 6-minute walk test (6MWT), the 9-hole peg test (9-HPT) Egen Klassification
Scale(EK), the North Star Ambulatory Assessment (NSAA), and quantitative key and pinch grip
strength testing.

Aim 9: To assess the reliability, validity and responsiveness of novel patient-reported
outcome(PRO) measures in DMD, including the NeuroQOL and PedsQL Neuromuscular Module.

Aim 10: To assess the clinical meaningfulness of novel objective clinical outcome measures
by assessing their ability to predict milestones of loss of ability to stand from supine, to
stand from a seated position, to climb stairs, to ambulate independently and to raise a hand
to the mouth.

AIM 11: To determine the impact of development and growth on outcome measure performance,we
will assess physical function on a group of healthy, typically developing male children and
adults between 6 and 30 years of age for outcome measures of motor function and strength
including the9-HPT, 6MWT, NSAA, timed function tests and quantitative muscle strength (QMT).
Test results from this cohort will be used to develop initial percent predicted for age
values for these assessments.

SNP Genotyping Study Aim

Our goal of the proposed study is to define polygenic modifiers of disease progression, and
also response to treatment with glucocorticoids (prednisone and deflazacort). The most
common type of human genetic variation is the single-nucleotide polymorphism (SNP, a base
position at which two alternative bases occur at an appreciable frequency (>1%) in the
population. SNPs are 90% of variation in the human genome. SNPs occur on the average of 1
per 1000 to 2000 bp throughout the 3.2 billion bp of the human genome while coding region
SNPs (cSNPs) occur on the average of 1 per 346 bp.

Genome-wide Association Study Aim

Our goal of the proposed study is to isolate genomic DNA and find possible correlations of
clinical phenotypes with gene loci associated with mild vs. severe clinical presentation,
progression, or response to steroids.

Serum Biomarkers Study Aim

Our goal is to discover and validate sensitive and specific serum biomarkers for DMD.

DMD Subject Inclusion Criteria

- Affected subjects must be male and between the ages of 2 and 30

- Affected subjects between the ages of 2 and 4 must have a diagnosis of DMD confirmed
by at least one the following OR have an older male sibling that meet at least one of
the following criteria:

- Dystrophin immunofluorescence and/or immunoblot showing complete dystrophin
deficiency, and clinical picture consistent with typical Duchenne dystrophy OR

- Gene deletion test positive (missing one or more exons) in the central rod
domain exons 25-60) of dystrophin, where reading frame can be predicted as
'out-of-frame',and clinical picture consistent with typical Duchenne dystrophy.

- Complete dystrophin gene sequencing showing an alteration (point mutation,
duplication, other) that is expected to preclude production of the dystrophin
protein(i.e. nonsense mutation, deletion/duplication leading to a downstream
stop codon),with a typical clinical picture of DMD.

- Affected subjects between the ages of 5 and 30 must either fulfill the above criteria
OR show evidence of a dystrophinopathy and clinical picture consistent with Duchenne
Muscular Dystrophy

- Participants who have documented clinical symptoms referable to a
dystrophinopathy and direct support of the diagnosis by either (1) a positive
DNA analysis for dystrophin mutation, (2) a muscle biopsy demonstrating abnormal
dystrophin, or (3) an elevated CK (>5X normal), and X-linked pedigree and an
affected family member who meets either criterion (1) or (2) as described above.

NOTE: Determination of the appropriate clinical symptoms consistent with DMD will
generally be the responsibility of the clinician. At a minimum this will include
progressive loss of function, with additional consideration for other clinical features
such as a characteristic gait, a positive Gower sign and calf pseudohypertrophy. When
immunostaining of muscle biopsy is used to determining case definition, the clinical
reviewer (site PI) should confirm that appropriate testing has ruled out a secondary
deficiency of dystrophin. Affected subjects that do not exhibit the above symptoms
consistent with DMD should be excluded.

o Muscle weakness prevalent by 5 years of age

- Non-affected adult subjects must be Parent(s) or legal guardian(s) of an eligible
affected subject.

DMD Serum Biomarker Inclusion Criteria

- Participants must meet eligibility criteria for the DMD phenotyping portion of this
study

- For the GC-treatment response cohort, participants must initiate GC treatment within
the first year of study participation (i.e. between their first study visit and their
one year follow-up visit)

DMD Subject Exclusion Criteria

For those subjects that confirm DMD diagnosis through a clinical picture consistent with
DMD

- Steroid-naïve subjects ambulating past the 13th birthday

- Steroid users ambulating past the 16th birthday

- Subjects/families who are unwilling or unable to comply with the protocol study
procedures or visits

Controls Subject Inclusion Criteria

- Male sex

- Age 6-30 years

- Able to comply with functional testing instructions

Control Serum Biomarker Inclusion criteria

- Participants must be male

- Participants must be free of DMD, other neuromuscular disease, or other significant
concomitant illness

- Participant must be free of glucocorticoid therapy

Control Subject Exclusion Criteria

- Musculoskeletal disease

- Musculoskeletal injury within 6 months of enrollment

- Other concomitant illness that precludes functional testing in the judgment of the
investigator or clinical evaluator

- Completion of enrollment for age cohort