Research Review No. 90.1.
A follow-up.
The Study:
In the next issue of the Journal, Neuromuscular Disorders, there was a
letter from Santiago de Compostela, Spain (7), which dealt with a further case of
Duchenne Muscular Dystrophy (DMD) with very mild symptoms. The author
describes a case of DMD, which he diagnosed in 1984 in a four-year old boy,
who had an uncle die of complications linked to DMD at the age of 26. “At that
time he had occasional falls when walking, waddling gait in early stage,
pseudohypertrophy of calves, depressed patellar reflexes, and he showed no
Gowers’ sign. His weight and height were appropriate for age. Serum CK was
12.000 U/L normal < 110 U/l), electromyography was myopathic, and biopsy of
the right vastus lateralis muscle showed a pattern of muscular dystrophy.” By the
age of 12, a minimal Gowers’ sign was noted, but he was able to walk without
difficulty and “climbed stairs without assistance at age 14, and with the aid of
railings at 18 years old.” Heart problems were detected when he was 20, which
worsened and he had a successful heart transplant at age 24. He was still able to
walk but lost the ability to walk unaided at age 30. “He lost the ability to stand up
from a seated position at age 33.
Currently, at 34 years and 10 months of age, he is dependent on a
wheelchair and transfer activities, and his cardiologic condition is stable and
uncomplicated.
A biopsy taken when he was 16 revealed a total absence of dystrophin,
and DNA studies detected the existence of a nonsense mutation in exon 9. The
author indicates the importance of such cases and stresses that these studies
must continue. He concludes that: “Our observations indicate that it is possible to
have a functional large muscle even without dystrophin.”
Reference:
7) Castro-Gago, M. (2015) Milder course in Duchenne patients with nonsense
mutations and no muscle dystrophin. Neuromuscular Disorders. 25(5):443-443.