A phenotypic study of a series of 91 Bulgarian Roma patients with congenital myasthenic syndrome linked to the homozygous c.1327delG mutation of the CHRNE gene, aged between one and 64 years, revealed three groups of differing severity:
- 44 patients, with an average age of 23.7 years, had a mild form; twenty-six others, with an average age of 20.2 years, had a moderate form; and a group of 21 patients, with an average age of 38.8 years, had a severe form;
- all patients, regardless of the severity of their disease, suffered from bulbar involvement, even though almost 56% of the ‘mild’ group did not complain about it and only the moderate and severe forms were affected by pulmonary aspirations;
- the presence of diplopia and ptosis was independent of disease severity and age;
Axial, proximal and distal muscle weakness were more marked in the more severe groups; - the mean vital capacity of the mild form group was 85.4% of theoretical in the sitting position and fell to 77.5% in the supine position, whereas it was 78% and 62.8% respectively in the sitting position for the moderate and severe form groups and fell by only 3 points in the supine position;
- only one patient suffering from the severe form was tracheotomised for one month because of pneumonia; no other patient in the series had used invasive or non-invasive assisted ventilation.
