In two decades, the Center for Genetic Diagnosis of Facioscapulohumeral Muscular Dystrophy (FSHD or FSH) in China (Fujian Neuromedical Centre) has collected and followed data from 997 patients with this myopathy and from 620 families. Their analysis shows that:
- on average, the number of D4Z4 repeat units is 5 (1 to 9 depending on the patient) and the level of methylation of the 4qA allele is 41% (14 to 69%);
- the first signs of muscle weakness appear at the median age of 16 years (1 to 81 years); 69.9% of patients have a typical FSH phenotype;
- 12% lost walking within 20 years of the onset of the very first symptoms, at the median age of 38 years (9 to 87 years), this risk being all the more important as the number of repeat units D4Z4 is weak and the disease early;
- the prevalence of FSH1 is established on Chinese territory at 0.75 per million inhabitants on average, with a record for the province of Fujian (7.1/106).
Voir aussi « FSH1 en Chine : près de 1 000 malades diagnostiqués en vingt ans »
