Limb-girdle muscular dystrophy subtypes in the population of Northeast China

The most common limb-girdle muscular dystrophy subtype in Italy, Spain, Turkey, Russia, Brazil and Australia is calpainopathy (limb-girdle muscular dystrophy type 2A), while dystroglycanopathy (limb-girdle muscular dystrophy type 2I) is the commonest form in Norway, Denmark and northern England. In India, sarcoglycanopthies (limb-girdle muscular dystrophy type 2C-2F) are the most preva-lent, while dysferlinopathies are the most frequent type in USA and Japan.

A rigorous comparison of the morphological features of biopsy specimens between limb-girdle muscular dystrophy type 2A and limb-girdle muscular dystrophy type 2B was therefore warranted. In China, the problem is complicated by the fact that, to the best of our knowledge, only two cohorts of patients with limb-girdle muscular dystrophy (15 cases in Shanghai and 8 cases in Jinan) have been published, each of which considered only one form of limb-girdle muscular dystrophy.

To the best of our knowledge, no cohort study rating the relative frequencies of different limb-girdle muscular dystrophy subtypes has been conducted in China. Dr. Xinmei Jiang and team from Affiliated First Hospital of Jilin University estimated the percentage of limb-girdle muscular dystrophy subtypes in Chinese people based on 68 patients with limb-girdle muscular dystrophy from the Myology Clinic, Neurology Department, First Hospital of Jilin University, China. A diagnosis of calpainopathy was made in 12 cases (17%), and dysferlin deficiency in 10 cases (15%). Two biopsies revealed α-sarcoglycan deficiency (3%), and two others revealed a lack of caveolin-3 (3%). A diagnosis of unclassified limb-girdle muscular dystrophy was made in the remaining patients (62%). The results suggest that the distribution of limb-girdle muscular dystrophy subtypes in the Han Chinese population is similar to that reported in the West. Calpainopathy is the most common form of limb-girdle muscular dystrophy in China, followed by dysferlinopathies. Muscle biopsy is a useful way to distinguish different subtypes.

These findings are published in the Neural Regeneration Research (Vol. 8, No. 20, 2013).

Provided by Neural Regeneration Research