engleski

Clinical, genetic and epidemiological study of calpainopathy (LGMD2A) in Croatia

INTRODUCTION. Autosomal recessive limb-girdle muscular dystrophies (LGMD2) form a group of muscle diseases presenting great clinical and genetic heterogeneity making an etiologic diagnosis very difficult and clinically in majority of patients impossible. In September 1998 we started a genetic and epidemiological study of muscular dystrophies (MDs) in Croatia. MATERIAL AND METHODS. Specific diagnostic strategy adapted to our country of 4, 4 million people was used. RESULTS. A 7-year long study showed that calpainopathy was the prevalent LGMD2. Analysis of 30 apparently unrelated families (47 patients) with calpain 3 (CAPN3) gene mutations and LGMD has discovered six different CAPN3 mutations: 550delA, R541W, P82L, delFWSAL, R49H, Y537X, accounting for 93% of CAPN3 chromosomes in the studied population. 550 delA was the prevalent mutation found on 43/60 (72%) analysed CAPN3 chromosomes ; other five mutations ranged from 8 to 2%. In 26 families two CAPN3 alleles were identified. In remaining 4 families with only one known CAPN3 allele, 550delA was present in 3 of 4 alleles, and P82L in one. DISCUSSION. Because of high frequency of healthy 550delA heterozygotes (1 in 133) and relative frequency of healthy heterozygotes for C826A mutation, which is responsible for LGMD2I (1 in 524) in our general population, we have decided to correlate genotype-phenotype only in patients with two known alleles. CONCLUSION. To study natural history of calpainopathy both alleles must be known as well as genetically homogenous groups should be follow up according to as simple as possible protocol.

limb girdle muscular dystrophy; autosomal recesive; LGMD2A; calpain3; Croatia; clinics; genetics; epidemiology; mutations

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