Clinical and genetic features of Calpainopathies in Saudi Arabia - a descriptive cross-sectional study

Limb-girdle muscular dystrophies (LGMD) is a heterogeneous group of genetic disorders characterized by progressive weakness of pelvic and shoulder girdle muscles. The objective is to characterize the phenotypic, pathological, radiological, and genetic findings in LGMD2A phenotype (Calpainopathies).

The National Saudi Arabian LGMD cohort database was screened for LGMD from January 2000 to January 2021. A descriptive cross-sectional study was done on a total of 112 families with LGMD. Screening for mutation in Calpain (CAPN3) gene was done. Clinical and genetic features of LGMD2A phenotype were the main outcome variables. Epi-info was used for statistical analysis.

34 subjects from 22 families (19.64%) had the specific LMGD2A phenotype. The mean age of onset was 9.9 ± 4.5 years (Range 4 to 19 years). The major initial symptoms were lower limb weakness, inability to climb stairs, and gait disturbance. Gower's sign occurred on an average of 3.75 to 7.25 years after onset. Loss of ambulation was observed in 55.8%. Two novel mutations in the CAPN3 gene were identified.

The prevalence of LGMD2A was 19.64% among the national Saudi Arabian LGMD cohort. The clinical presentation was varied and was consistent with other reports from different ethnic groups.