Genetic diagnosis of facioscapulohumeral muscular dystrophy (FSHD) using southern blotting with non-radioactive probes

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly inherited disease that characterized with in-volvement and weakness of the facial and scapular muscles. It’s one of the most common forms of myopathies with prevalence 1:7500-1:15000. FSHD is caused by genetic and epigenetic factors and can be classified into two subgroups: FSHD1 and FSHD2. FSHD1-accounts for around 95% of the cases- is associated with contraction of D4Z4 macrosatellites at the subtelomeric region of chromosome-4. Normal individuals carry 11-110 repeats whereas affected individuals have 1-11 D4Z4 repeats-. But, FSHD2 is linked to mutations in SMCHD1 gene on repeats and chromosome-18. Previous studies indicate a negative correlation between the number of D4Z4 the disease severity. This study has investigated the clinical and genetic aspects of Iranian FSHD patients. The patients were recruited from all provinces of Iran. All cases consented to participate after being informed about repeats- using non-radioactive the project. The southern blot -the gold standard technique for analyzing of D4Z4 probes was optimized. The southern blot for FSHD includes, EcoRI digestion, double digestion with EcoRI/BlnI, electrophoresis, transfer of the fragments on the nylon membrane, hybridization with Dig labeled probe, detec-tion and analysis of fragments. All the patients had less than nine D4Z4 repeats so they affected to FSHD type 1. Patients with less number of repeats were more severe affected. So, there are significant correlation betweennumber of repeats and disease severity and age at onset

کلیدواژه ها:

D4Z4 repeats ، Facioscapulohumeral muscular dystrophy ، FSHD ، Macro-satellite ، Southern blot