Diagnosing Duchenne case studies

‘C’ presented with symptoms of developmental delay at 20 months. C was unable to babble or speak, and communicated only through signing.

What would you do?

Speech delay and language impairment should trigger a creatine kinase (CK) test.

C was placed in a school for children with severe learning difficulties.

What would you do?

Learning difficulties should trigger a CK test.

At the age of 6 years, teachers reported concerns about bruising, which was attributed to frequent falls.

What would you do?

Frequent falls should trigger a CK test.

C was referred to a paediatric neurologist for further assessment.

Physical examination revealed calf hypertrophy, a waddling gait and use of Gowers’ manoeuvre to get up from the floor. Laboratory tests were ordered.

What would you do?

Calf hypertrophy, abnormal gait or Gowers’ manoeuvre should trigger a CK test.

C’s tests revealed his CK concentration levels were >9,000 U/L, elevated well above normal levels (normal level ≤250 U/L).

What would you do?

All patients with elevated CK levels should be referred to a neuromuscular specialist.

No deletion in the dystrophin gene was detected, but muscle biopsy showed dystrophic histochemistry and absence of dystrophin.

What would you do?

Genetic testing should be used to determine the specific mutation causing DMD. If initial genetic analysis is negative, the analysis of small and microdeletion/duplication gene mutations should be carried out.

At the age of 6, C was diagnosed with DMD.

The delay between onset of symptoms and time of definitive diagnosis for C meant he wasn’t receiving optimal management for his DMD during this time. By this time, he had lost a significant amount of muscle function.

Prompt intervention is critical to help delay disease progression and help preserve muscle function for as long as possible.

How can you help?

If you see signs and symptoms of DMD, order a CK test.

At 24 months’ of age, ‘M’ was brought to his GP because his parents were concerned that he was unable to communicate. He showed no signs of being able to gesture, babble or speak, and had started walking at 23 months.

What would you do?

Speech delay and language impairment should trigger a CK test​.

M’s GP ordered metabolic and chromosomal tests, which came back normal. A CK test wasn’t carried out.

What would you do?

Developmental delay should trigger a CK test.

M was referred for a special educational needs assessment, which identified learning difficulties. He was subsequently placed in a school for children with learning disabilities.

What would you do?

Learning difficulties should trigger a CK test.

M’s younger brother, C, was diagnosed with DMD at the age of 6. Shortly afterwards, M was reassessed by a paediatric neurologist who ordered more laboratory tests.

What would you do?

A family history of DMD and suspicion of abnormal muscle function should trigger a
CK test.

M’s serum CK concentration was >10,000 U/L, elevated well above normal levels
(normal level: ≤250 U/L).

What would you do?

All patients with elevated CK levels should be referred to a neuromuscular specialist.

Genetic testing identified a deletion mutation in the dystrophin gene that included
exons 3–8.

What would you do?

Genetic testing should be used to determine the specific mutation causing DMD.

At the age of 7 years and 6 months, M was diagnosed with DMD.

The 5.5-year delay between onset of symptoms and time of definitive diagnosis for M meant he wasn’t receiving optimal management for his DMD during this time. By age 7, he had fallen behind in education and was not receiving the most appropriate support.

Starting treatment as soon as possible is vital to help slow DMD progression and avoid further muscle deterioration.

How can you help?

If you see signs and symptoms of DMD, order a CK test.

‘T’ was brought to his GP by his mother because he was not able to speak or even babble at 16 months old. His mother also reported that T often walked on his toes when he began to walk at 13 months.​

What would you do?

Developmental delay should trigger a CK test​.

At 2 years old, T underwent a multidisciplinary assessment at a child development centre and was diagnosed with language delay and learning difficulties. He was later provided special education and support services at primary school.

What would you do?

Developmental delay should trigger a CK test.

At 5 years, T’s teacher reported concerns about his motor skills.

What would you do?

Motor function delay should trigger a CK test.

At 5 years and 4 months, T was referred to a paediatric neurologist for further assessment.

Physical examination revealed calf hypertrophy, a waddling gait and use of Gowers’ manoeuvre to get up from the floor.

What would you do?

Calf hypertrophy, abnormal gait or Gowers’ manoeuvre should trigger a CK test.​

Laboratory tests were ordered. T’s CK concentration levels were >10,000 U/L, well above normal levels (normal level ≤250 U/L).

What would you do?

All patients with elevated CK levels should be referred to a neuromuscular specialist.

Genetic testing identified a deletion mutation in the dystrophin gene that included
exons 3–8.

What would you do?

Genetic testing should be used to determine the specific mutation causing DMD.

T was diagnosed with DMD around 4 years after he first presented with symptoms, at the age of 5 years and 4 months.

The 4-year delay between onset of symptoms and time of definitive diagnosis for T meant he wasn’t receiving optimal management for his DMD during this time. At the age of 8 years 7 months, he could walk only a few metres indoors.

In order to help slow disease progression and maintain muscle function for as long as possible, treatment should be initiated as early as possible.

How you can help?

If you see signs and symptoms of DMD, order a CK test.