| Scheda |
| Features
|
Myotonia
associated with progressive weakness. |
| Etiology |
Presence
of an altered protein, myotonin, due to a mutation in the coding
gene (chromosome 19). |
Heredity
|
Autosomal
dominant. |
Affected
sex
|
Male
and female. |
Clinical
onset
|
Variable,
from congenital to the first two decades of life. |
Evolution
|
Progressive,
irreversible. |
Initially
involved muscles
|
Face
and distal limb muscles. |
Onset
symptoms
|
Myotonia
(slow muscle relaxation). |
Disability
|
Variable,
no wheelchair. |
Exitus
|
Variable,
typically around age 50-60 years. |
Spared
muscles
|
None,
but limb girdles are affected late. |
| Other
features |
Cardiac,
ocular, endocrine signs and symptoms, rarely intellective impairment. |
