A Chinese multicentre study (covering 9 regions) describes the clinical course and phenotype-genotype correlations of a cohort of children with LAMA2 muscular dystrophy, 116 congenital forms with a median age of 6.4 years (0.3 to 27.3 years) at the last visit, 14 girdle forms (LGMDR23) with a median age of 8.2 years (3.2 to 27 years) at the last visit.
- The first symptoms (hypotonia, faint crying, difficulty suckling, breathing difficulties) appear between 0 and 6 months in children with a congenital form, and in the first week of life in three-quarters of these cases. The median age of onset of first symptoms (myopathic gait, difficulty running and/or jumping, epilepsy) in children with a girdle form (LGMDR23) is 18 months (13 months to 13 years).
- Epileptic seizures were present in 9.5% of children with a congenital form (9 cases of epilepsy, 2 cases of febrile convulsions) and 35% of children with a girdle form (LGMDR23) (3 cases of epilepsy, 2 cases of febrile convulsions).
- Electrocardiogram and echocardiography performed in 63 children did not reveal any specific abnormalities. Only one infant aged 1.8 years had a reduced left ventricular ejection fraction which returned to normal after 2 years of treatment with captopril.
- Nearly 60% of children with a congenital form, aged over two years, had difficulty chewing, and 12% had difficulty swallowing.
- Twenty-three children with a congenital form and one child with a girdle form died at a median age of 7.9 years (0.3 to 18 years). The other 106 children are still alive, at a median age of 6.5 years (0.5 to 27.3 years).
- The genotype-phenotype correlations show that splicing abnormalities appear to be associated with relatively moderate congenital forms; nonsense mutations are more common in the congenital form whereas missense mutations are more common in the girdle form (LGMDR23); variations in the number of copies appear to have a lower survival rate.
